diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..ccc7da8
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,2 @@
+# Preserve MIME fixtures byte-for-byte, including CRLF header separators.
+Tests/Fixtures/Eml/*.eml binary
diff --git a/.github/workflows/eml.yml b/.github/workflows/eml.yml
new file mode 100644
index 0000000..7befbff
--- /dev/null
+++ b/.github/workflows/eml.yml
@@ -0,0 +1,40 @@
+name: EML parser
+
+on:
+  push:
+    branches: [master]
+    paths: ['Convert-EmlFile.ps1', 'Private/Import-EmlMimeKit.ps1', 'scripts/Install-EmlDependency.ps1', 'Tests/Convert-EmlFile.Tests.ps1', 'Tests/Fixtures/Eml/**', '.github/workflows/eml.yml']
+  pull_request:
+    paths: ['Convert-EmlFile.ps1', 'Private/Import-EmlMimeKit.ps1', 'scripts/Install-EmlDependency.ps1', 'Tests/Convert-EmlFile.Tests.ps1', 'Tests/Fixtures/Eml/**', '.github/workflows/eml.yml']
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 15
+    defaults:
+      run:
+        shell: pwsh
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+      - name: Install EML parser dependency
+        run: ./scripts/Install-EmlDependency.ps1
+      - name: Install and run Pester
+        run: |
+          $ErrorActionPreference = 'Stop'
+          Install-Module Pester -RequiredVersion 5.7.1 -Scope CurrentUser -Force -Repository PSGallery
+          Import-Module Pester -RequiredVersion 5.7.1 -Force
+          $configuration = New-PesterConfiguration
+          $configuration.Run.Path = './Tests'
+          $configuration.Run.Exit = $true
+          $configuration.Output.Verbosity = 'Detailed'
+          Invoke-Pester -Configuration $configuration
diff --git a/.github/workflows/guid.yml b/.github/workflows/guid.yml
index e15a539..31d5792 100644
--- a/.github/workflows/guid.yml
+++ b/.github/workflows/guid.yml
@@ -26,6 +26,8 @@ jobs:
       - uses: actions/checkout@v6
         with:
           persist-credentials: false
+      - name: Install EML parser dependency
+        run: ./scripts/Install-EmlDependency.ps1
       - name: Install and run Pester
         run: |
           $ErrorActionPreference = 'Stop'
diff --git a/.github/workflows/registry.yml b/.github/workflows/registry.yml
index 91be334..afaa57d 100644
--- a/.github/workflows/registry.yml
+++ b/.github/workflows/registry.yml
@@ -26,6 +26,8 @@ jobs:
       - uses: actions/checkout@v6
         with:
           persist-credentials: false
+      - name: Install EML parser dependency
+        run: ./scripts/Install-EmlDependency.ps1
       - name: Install and run Pester
         run: |
           $ErrorActionPreference = 'Stop'
diff --git a/.github/workflows/upn.yml b/.github/workflows/upn.yml
index 0935c07..8d7223e 100644
--- a/.github/workflows/upn.yml
+++ b/.github/workflows/upn.yml
@@ -26,6 +26,8 @@ jobs:
       - uses: actions/checkout@v6
         with:
           persist-credentials: false
+      - name: Install EML parser dependency
+        run: ./scripts/Install-EmlDependency.ps1
       - name: Install and run Pester
         run: |
           $ErrorActionPreference = 'Stop'
diff --git a/.gitignore b/.gitignore
index df2610d..048eb4d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,4 @@
 *.TempPoint.ps1
+
+# Locally installed EML parser dependency
+.eml-dependencies/
diff --git a/Convert-EmlFile.ps1 b/Convert-EmlFile.ps1
index 2bbb674..9fccd11 100644
--- a/Convert-EmlFile.ps1
+++ b/Convert-EmlFile.ps1
@@ -1,45 +1,111 @@
-function Convert-EmlFile
+#Requires -Version 7.4
+
+. (Join-Path $PSScriptRoot 'Private/Import-EmlMimeKit.ps1')
+$script:EmlDefaultAssemblyPath = Join-Path $PSScriptRoot '.eml-dependencies/MimeKitLite/4.18.1/MimeKitLite.dll'
+
+function Convert-EmlFile
 {
-<#
+    <#
     .SYNOPSIS
-        Function will parse an eml files.
-
+        Parses local MIME messages into detached PowerShell objects.
     .DESCRIPTION
-        Function will parse eml file and return a normalized object that can be used to extract infromation from the encoded file.
-
-    .PARAMETER EmlFileName
-        A string representing the eml file to parse.
-
-    .EXAMPLE
-        PS C:\> Convert-EmlFile -EmlFileName 'C:\Test\test.eml'
-
-    .OUTPUTS
-        System.Object
-#>
+        Uses a pinned MimeKitLite dependency installed explicitly, never downloaded
+        during parsing. Returns decoded bodies, mailbox lists, repeated headers and
+        attachment metadata. Does not extract attachments, render HTML, validate
+        signatures, decrypt content or return live parser/COM objects.
+        File and parser errors terminate. MaxFileSizeBytes bounds input size only.
+    #>
     [CmdletBinding()]
-    [OutputType([object])]
-    param
-    (
-        [Parameter(Mandatory = $true)]
+    [OutputType([pscustomobject])]
+    param (
+        [Parameter(Mandatory, Position = 0, ValueFromPipeline, ValueFromPipelineByPropertyName)]
+        [Alias('FullName')]
         [ValidateNotNullOrEmpty()]
-        [string]
-        $EmlFileName
-    )
+        [string[]]$EmlFileName,
 
-    # Instantiate new ADODB Stream object
-    $adoStream = New-Object -ComObject 'ADODB.Stream'
-
-    # Open stream
-    $adoStream.Open()
-
-    # Load file
-    $adoStream.LoadFromFile($EmlFileName)
-
-    # Instantiate new CDO Message Object
-    $cdoMessageObject = New-Object -ComObject 'CDO.Message'
-
-    # Open object and pass stream
-    $cdoMessageObject.DataSource.OpenObject($adoStream, '_Stream')
+        [ValidateNotNullOrEmpty()]
+        [string]$MimeKitPath = $script:EmlDefaultAssemblyPath,
 
-    return $cdoMessageObject
-}
\ No newline at end of file
+        [ValidateRange(1, 1073741824)]
+        [long]$MaxFileSizeBytes = 26214400
+    )
+    begin { Import-EmlMimeKit -AssemblyPath $MimeKitPath }
+    process
+    {
+        foreach ($fileName in $EmlFileName)
+        {
+            $file = Get-Item -LiteralPath $fileName -ErrorAction Stop
+            if ($file.PSProvider.Name -ne 'FileSystem' -or $file.PSIsContainer)
+            {
+                throw "EML input must be a filesystem file: $fileName"
+            }
+            $stream = $null
+            $message = $null
+            try
+            {
+                $stream = [System.IO.File]::Open($file.FullName, [System.IO.FileMode]::Open, [System.IO.FileAccess]::Read, [System.IO.FileShare]::Read)
+                if ($stream.Length -eq 0 -or $stream.Length -gt $MaxFileSizeBytes)
+                {
+                    throw [System.IO.InvalidDataException]::new("EML input must be nonempty and at most $MaxFileSizeBytes bytes: $($file.FullName)")
+                }
+                $message = [MimeKit.MimeMessage]::Load($stream, $false, [System.Threading.CancellationToken]::None)
+                if ($message.Headers.Count -eq 0)
+                {
+                    throw [System.FormatException]::new('EML input contains no parsed message headers.')
+                }
+                $mailboxes = @{}
+                foreach ($field in @('From', 'To', 'Cc', 'Bcc', 'ReplyTo'))
+                {
+                    $mailboxes[$field] = @($message.$field.Mailboxes | ForEach-Object {
+                        [pscustomobject]@{ Name = [string]$_.Name; Address = [string]$_.Address }
+                    })
+                }
+                $attachments = @(
+                    foreach ($part in $message.BodyParts)
+                    {
+                        $isAttachment = $part.IsAttachment
+                        $disposition = $part.ContentDisposition
+                        $isInline = ($null -ne $disposition -and $disposition.Disposition -eq 'inline') -or
+                            (-not $isAttachment -and -not [string]::IsNullOrEmpty($part.ContentId) -and $part -isnot [MimeKit.TextPart])
+                        if (-not $isAttachment -and -not $isInline) { continue }
+                        $attachmentName = if ($null -ne $disposition) { $disposition.FileName } else { $null }
+                        if ([string]::IsNullOrEmpty($attachmentName)) { $attachmentName = $part.ContentType.Name }
+                        [pscustomobject]@{
+                            FileName = $attachmentName
+                            MimeType = [string]$part.ContentType.MimeType
+                            ContentId = $part.ContentId
+                            IsInline = [bool]$isInline
+                            IsAttachedMessage = [bool]($part -is [MimeKit.MessagePart])
+                        }
+                    }
+                )
+                $date = $null
+                if ($message.Headers.Contains('Date') -and $message.Date -ne [DateTimeOffset]::MinValue)
+                {
+                    $date = $message.Date
+                }
+                [pscustomobject]@{
+                    PSTypeName = 'StandaloneFunctions.EmlMessage'
+                    SourcePath = $file.FullName
+                    MessageId = $message.MessageId
+                    Subject = $message.Subject
+                    Date = $date
+                    From = $mailboxes.From
+                    To = $mailboxes.To
+                    Cc = $mailboxes.Cc
+                    Bcc = $mailboxes.Bcc
+                    ReplyTo = $mailboxes.ReplyTo
+                    TextBody = $message.TextBody
+                    HtmlBody = $message.HtmlBody
+                    Headers = @($message.Headers | ForEach-Object { [pscustomobject]@{ Field = [string]$_.Field; Value = [string]$_.Value } })
+                    Attachments = $attachments
+                }
+            }
+            finally
+            {
+                if ($null -ne $message) { $message.Dispose() }
+                if ($null -ne $stream) { $stream.Dispose() }
+            }
+        }
+    }
+}
diff --git a/Private/Import-EmlMimeKit.ps1 b/Private/Import-EmlMimeKit.ps1
new file mode 100644
index 0000000..648bdc9
--- /dev/null
+++ b/Private/Import-EmlMimeKit.ps1
@@ -0,0 +1,29 @@
+function Import-EmlMimeKit
+{
+    [CmdletBinding()]
+    param ([Parameter(Mandatory)][string]$AssemblyPath)
+
+    $expectedHash = '437939ba9f01228cc19dd9f755d5e77cac1fd44a8c2b076ed35b927aa625306c'
+    if (-not (Test-Path -LiteralPath $AssemblyPath -PathType Leaf))
+    {
+        throw 'MimeKitLite dependency not found. Run ./scripts/Install-EmlDependency.ps1 once, or supply MimeKitPath. Parsing never downloads dependencies.'
+    }
+    $path = (Get-Item -LiteralPath $AssemblyPath -Force -ErrorAction Stop).FullName
+    if ((Get-FileHash -LiteralPath $path -Algorithm SHA256).Hash -ine $expectedHash)
+    {
+        throw 'Unexpected MimeKitLite binary. Use the pinned net8.0 assembly installed by Install-EmlDependency.ps1.'
+    }
+    $loadedType = 'MimeKit.MimeMessage' -as [type]
+    if ($null -ne $loadedType)
+    {
+        $assembly = $loadedType.Assembly
+        if ($assembly.GetName().Name -ne 'MimeKitLite' -or
+            [string]::IsNullOrWhiteSpace($assembly.Location) -or
+            (Get-FileHash -LiteralPath $assembly.Location -Algorithm SHA256).Hash -ine $expectedHash)
+        {
+            throw 'A conflicting MimeKit assembly is already loaded. Start a clean PowerShell process for this pinned parser.'
+        }
+        return
+    }
+    [void][System.Reflection.Assembly]::LoadFrom($path)
+}
diff --git a/README.md b/README.md
index b213d05..182b54d 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,10 @@ The standalone OAuth-style request helper now follows the IT-ToolBox implementat
 
 `Get-UniqueUPN` and `Test-UPNExist` now use explicit forest/domain lookup scope, escaped LDAP equality filters, bounded collision checks and independent name formatting. They require PowerShell 7.4; actual lookups additionally require the ActiveDirectory module and directory connectivity. See [usage and compatibility notes](./docs/UPN.md). These are availability checks, not atomic reservations.
 
+### Convert-EmlFile
+
+Cross-platform MIME parsing now replaces the Windows-only COM result with detached message objects. Requires PowerShell 7.4 and explicit installation of pinned MimeKitLite: `./scripts/Install-EmlDependency.ps1`. Parsing itself never downloads dependencies. See [output schema and migration notes](./docs/Convert-EmlFile.md), especially changes from CDO.Message.
+
 ## Standalone functions
 
 The repository also contains standalone utilities including:
@@ -46,7 +50,7 @@ The repository also contains standalone utilities including:
 - [`Get-TimerStatus`](./Get-TimerStatus.ps1) — returns the running state of a stopwatch
 - [`New-ApiRequest`](./New-ApiRequest.ps1) — helper for API calls using OAuth2 authentication
 - [`Test-IsGuid`](./Test-IsGuid.ps1) — validates GUID strings
-- [`Convert-EmlFile`](./Convert-EmlFile.ps1) — converts `.eml` files into PowerShell objects
+- [`Convert-EmlFile`](./Convert-EmlFile.ps1) — parses local MIME messages into detached PowerShell objects
 - [`New-StringConversion`](./New-StringConversion.ps1) — handles selected string/character conversion scenarios
 - [`Test-IsRegistryKey`](./Test-IsRegistryKey.ps1) — validates registry keys for use by `Export-Registry`
 - [`Export-Registry`](./Export-Registry.ps1) — exports registry data to CSV or XML
diff --git a/Tests/Convert-EmlFile.Tests.ps1 b/Tests/Convert-EmlFile.Tests.ps1
new file mode 100644
index 0000000..c7df573
--- /dev/null
+++ b/Tests/Convert-EmlFile.Tests.ps1
@@ -0,0 +1,132 @@
+BeforeAll {
+    . (Join-Path $PSScriptRoot '../Convert-EmlFile.ps1')
+    $fixtures = Join-Path $PSScriptRoot 'Fixtures/Eml'
+}
+Describe 'EML normalization with real MimeKitLite parsing' {
+    It 'decodes headers, mailbox groups and text content' {
+        $r=Convert-EmlFile (Join-Path $fixtures 'plain.eml')
+        $r.Subject | Should -BeExactly 'café'
+        $r.From.Count | Should -Be 1
+        $r.From[0].Name | Should -BeExactly 'Jörg'
+        $r.From[0].Address | Should -BeExactly 'sender@example.com'
+        $r.To.Count | Should -Be 2
+        $r.Cc.Count | Should -Be 1
+        $r.Bcc.Count | Should -Be 0
+        $r.ReplyTo[0].Address | Should -BeExactly 'replies@example.com'
+        $r.TextBody.Trim() | Should -BeExactly 'café'
+        $r.MessageId | Should -BeExactly 'plain@example.com'
+        $r.Date | Should -BeOfType ([DateTimeOffset])
+        $r.Date.Offset.TotalHours | Should -Be 2
+    }
+    It 'works under StrictMode with absent optional fields' {
+        Set-StrictMode -Version Latest
+        $r=Convert-EmlFile (Join-Path $fixtures 'plain.eml')
+        $r.Attachments.Count | Should -Be 0
+        $r.Subject | Should -BeExactly 'café'
+    }
+    It 'preserves repeated headers in sequence' {
+        $r=Convert-EmlFile (Join-Path $fixtures 'plain.eml')
+        $values=@($r.Headers | Where-Object Field -eq 'X-Trace' | ForEach-Object Value)
+        $values.Count | Should -Be 2
+        ($values -join ',') | Should -BeExactly 'first,second'
+    }
+    It 'returns empty arrays and missing-body/date nulls for a header-only message' {
+        $r=Convert-EmlFile (Join-Path $fixtures 'header-only.eml')
+        $r.From.Count | Should -Be 0
+        $r.Attachments.Count | Should -Be 0
+        $r.Date | Should -BeNullOrEmpty
+        $r.TextBody | Should -BeNullOrEmpty
+        $r.HtmlBody | Should -BeNullOrEmpty
+    }
+    It 'decodes an older charset and quoted-printable body' {
+        (Convert-EmlFile (Join-Path $fixtures 'latin1.eml')).TextBody.Trim() | Should -BeExactly 'café'
+    }
+    It 'handles multipart bodies, inline metadata and an attached message' {
+        $r=Convert-EmlFile (Join-Path $fixtures 'multipart.eml')
+        $r.TextBody | Should -Match 'Plain body'
+        $r.HtmlBody | Should -Match '<p>HTML body</p>'
+        $r.Attachments.Count | Should -Be 3
+        ($r.Attachments | Where-Object FileName -eq '../danger.txt').MimeType | Should -BeExactly 'application/octet-stream'
+        ($r.Attachments | Where-Object IsInline).ContentId | Should -BeExactly 'image-one'
+        ($r.Attachments | Where-Object IsAttachedMessage).FileName | Should -BeExactly 'forwarded.eml'
+    }
+    It 'includes inline Content-ID parts without a disposition header' {
+        $path=Join-Path $TestDrive 'cid.eml'
+        $text=[System.IO.File]::ReadAllText((Join-Path $fixtures 'multipart.eml'))
+        $text=$text -replace '(?m)^Content-Disposition: inline; filename="image.png"\r?\n', ''
+        [System.IO.File]::WriteAllText($path,$text)
+        $r=Convert-EmlFile $path
+        $inline=@($r.Attachments | Where-Object IsInline)
+        $inline.Count | Should -Be 1
+        $inline[0].ContentId | Should -BeExactly 'image-one'
+        $inline[0].FileName | Should -BeNullOrEmpty
+    }
+    It 'does not extract attachments or render/fetch HTML' {
+        Mock Invoke-WebRequest {throw 'Parsing must not make network calls'}
+        $sandbox=New-Item -ItemType Directory -Path (Join-Path $TestDrive 'no-extraction')
+        Push-Location $sandbox.FullName
+        try {
+            $null=Convert-EmlFile (Join-Path $fixtures 'multipart.eml')
+            @(Get-ChildItem -Force $sandbox.FullName).Count | Should -Be 0
+            Should -Invoke Invoke-WebRequest -Times 0 -Exactly
+        } finally {Pop-Location}
+    }
+    It 'returns detached data that survives source deletion and serializes' {
+        $path=Join-Path $TestDrive 'copy.eml'
+        Copy-Item (Join-Path $fixtures 'multipart.eml') $path
+        $r=Convert-EmlFile $path
+        # FileShare.None would fail on Windows if the source stream was left open.
+        $stream=[System.IO.File]::Open($path,[System.IO.FileMode]::Open,[System.IO.FileAccess]::ReadWrite,[System.IO.FileShare]::None)
+        $stream.Dispose()
+        Remove-Item $path
+        $r.TextBody | Should -Match 'Plain body'
+        $r.Attachments[0].GetType().Name | Should -BeExactly 'PSCustomObject'
+        ($r | ConvertTo-Json -Depth 10) | Should -Match 'forwarded.eml'
+    }
+    It 'uses literal filenames and returns one message per pipeline record' {
+        $path=Join-Path $TestDrive 'mail[1].eml'
+        Copy-Item (Join-Path $fixtures 'plain.eml') -Destination $path
+        $rows=@(@($path,(Join-Path $fixtures 'header-only.eml')) | Convert-EmlFile)
+        $rows.Count | Should -Be 2
+        $rows[0].SourcePath | Should -BeExactly $path
+    }
+    It 'supports FileInfo input through its FullName property' {
+        $r=Get-Item (Join-Path $fixtures 'plain.eml') | Convert-EmlFile
+        $r.Subject | Should -BeExactly 'café'
+    }
+    It 'rejects missing files, directories, zero-length and headerless input' {
+        {Convert-EmlFile (Join-Path $TestDrive 'missing.eml')} | Should -Throw
+        {Convert-EmlFile $TestDrive} | Should -Throw '*filesystem file*'
+        $empty=Join-Path $TestDrive 'empty.eml';[System.IO.File]::WriteAllBytes($empty,[byte[]]@())
+        {Convert-EmlFile $empty} | Should -Throw '*nonempty*'
+        {Convert-EmlFile (Join-Path $fixtures 'invalid.eml')} | Should -Throw
+    }
+    It 'honors the input-size boundary' {
+        $path=Join-Path $fixtures 'plain.eml';$size=(Get-Item $path).Length
+        {Convert-EmlFile $path -MaxFileSizeBytes ($size-1)} | Should -Throw '*at most*'
+        (Convert-EmlFile $path -MaxFileSizeBytes $size).Subject | Should -BeExactly 'café'
+        {Convert-EmlFile $path -MaxFileSizeBytes 0} | Should -Throw
+    }
+    It 'reports missing or unexpected binaries without downloading them' {
+        Mock Invoke-WebRequest {throw 'No implicit downloads'}
+        {Convert-EmlFile (Join-Path $fixtures 'plain.eml') -MimeKitPath (Join-Path $TestDrive 'missing.dll')} | Should -Throw '*dependency not found*'
+        $fake=Join-Path $TestDrive 'wrong.dll';Set-Content $fake 'not a DLL'
+        {Convert-EmlFile (Join-Path $fixtures 'plain.eml') -MimeKitPath $fake} | Should -Throw '*Unexpected MimeKitLite binary*'
+        Should -Invoke Invoke-WebRequest -Times 0 -Exactly
+    }
+}
+Describe 'Dependency installer behavior' {
+    It 'supports WhatIf without downloading or creating directories' {
+        Mock Invoke-WebRequest {throw 'No download expected'}
+        $path=Join-Path $TestDrive 'not-installed'
+        & (Join-Path $PSScriptRoot '../scripts/Install-EmlDependency.ps1') -Destination $path -WhatIf
+        Test-Path $path | Should -BeFalse
+        Should -Invoke Invoke-WebRequest -Times 0 -Exactly
+    }
+    It 'rejects altered packages before installation' {
+        Mock Invoke-WebRequest {Set-Content -LiteralPath $OutFile 'corrupt package'}
+        $path=Join-Path $TestDrive 'bad-install'
+        {& (Join-Path $PSScriptRoot '../scripts/Install-EmlDependency.ps1') -Destination $path} | Should -Throw '*checksum mismatch*'
+        Test-Path $path | Should -BeFalse
+    }
+}
diff --git a/Tests/Fixtures/Eml/header-only.eml b/Tests/Fixtures/Eml/header-only.eml
new file mode 100644
index 0000000..f1b6bd0
--- /dev/null
+++ b/Tests/Fixtures/Eml/header-only.eml
@@ -0,0 +1,3 @@
+Subject: Headers only
+X-Test: value
+
diff --git a/Tests/Fixtures/Eml/invalid.eml b/Tests/Fixtures/Eml/invalid.eml
new file mode 100644
index 0000000..69f4c77
--- /dev/null
+++ b/Tests/Fixtures/Eml/invalid.eml
@@ -0,0 +1,2 @@
+Not an email message
+No field delimiters here
diff --git a/Tests/Fixtures/Eml/latin1.eml b/Tests/Fixtures/Eml/latin1.eml
new file mode 100644
index 0000000..a28a71f
--- /dev/null
+++ b/Tests/Fixtures/Eml/latin1.eml
@@ -0,0 +1,6 @@
+From: sender@example.com
+Subject: Latin charset
+Content-Type: text/plain; charset=iso-8859-1
+Content-Transfer-Encoding: quoted-printable
+
+caf=E9
diff --git a/Tests/Fixtures/Eml/multipart.eml b/Tests/Fixtures/Eml/multipart.eml
new file mode 100644
index 0000000..6d0c93e
--- /dev/null
+++ b/Tests/Fixtures/Eml/multipart.eml
@@ -0,0 +1,41 @@
+From: sender@example.com
+To: receiver@example.com
+Subject: Multipart sample
+MIME-Version: 1.0
+Content-Type: multipart/mixed; boundary="outer"
+
+--outer
+Content-Type: multipart/alternative; boundary="alt"
+
+--alt
+Content-Type: text/plain; charset=utf-8
+
+Plain body
+--alt
+Content-Type: text/html; charset=utf-8
+
+<p>HTML body</p><img src="https://example.invalid/never-fetch">
+--alt--
+--outer
+Content-Type: application/octet-stream; name="../danger.txt"
+Content-Disposition: attachment; filename="../danger.txt"
+Content-Transfer-Encoding: base64
+
+c2FtcGxl
+--outer
+Content-Type: image/png
+Content-Disposition: inline; filename="image.png"
+Content-Id: <image-one>
+Content-Transfer-Encoding: base64
+
+aW1hZ2U=
+--outer
+Content-Type: message/rfc822
+Content-Disposition: attachment; filename="forwarded.eml"
+
+From: nested@example.com
+To: receiver@example.com
+Subject: Nested message
+
+Nested body
+--outer--
diff --git a/Tests/Fixtures/Eml/plain.eml b/Tests/Fixtures/Eml/plain.eml
new file mode 100644
index 0000000..fa39c22
--- /dev/null
+++ b/Tests/Fixtures/Eml/plain.eml
@@ -0,0 +1,14 @@
+From: =?utf-8?Q?J=C3=B6rg?= <sender@example.com>
+To: Team: Alice <alice@example.com>, Bob <bob@example.com>;
+Cc: copy@example.com
+Reply-To: replies@example.com
+Subject: =?utf-8?Q?caf=C3=A9?=
+Date: Sat, 24 Oct 2026 10:30:00 +0200
+Message-Id: <plain@example.com>
+X-Trace: first
+X-Trace: second
+MIME-Version: 1.0
+Content-Type: text/plain; charset=utf-8
+Content-Transfer-Encoding: base64
+
+Y2Fmw6kK
diff --git a/docs/Convert-EmlFile.md b/docs/Convert-EmlFile.md
new file mode 100644
index 0000000..2f3a49d
--- /dev/null
+++ b/docs/Convert-EmlFile.md
@@ -0,0 +1,73 @@
+# Convert-EmlFile: cross-platform MIME parsing
+
+## Install once
+
+Requires PowerShell 7.4+ (.NET 8+) and MimeKitLite 4.18.1. No IT-ToolBox installation is required; that module is not modified. MimeKitLite is the upstream MimeKit parser without most cryptography features. The net8.0 asset has no NuGet dependencies.
+
+From the repository, in PowerShell:
+
+```powershell
+./scripts/Install-EmlDependency.ps1
+. ./Convert-EmlFile.ps1
+$message = Convert-EmlFile -EmlFileName './message.eml'
+$message.Subject
+$message.To
+$message.Attachments
+```
+
+Only the explicit installer uses the network. It downloads a pinned NuGet package over HTTPS, checks its SHA-256, and extracts the net8.0 assembly. The original package is retained with its upstream MIT licensing metadata. Files go under ignored .eml-dependencies/MimeKitLite/4.18.1/. Nothing is installed globally. WhatIf performs no writes/downloads. A new custom destination can be selected with Destination; pass its DLL to Convert-EmlFile through MimeKitPath.
+
+Keep Private/Import-EmlMimeKit.ps1 with the root function. Both package and DLL hashes are pinned; different releases require an intentional dependency update, updated hashes and regression tests. A conflicting MimeKit assembly in the current process produces an error: restart PowerShell rather than trying to replace a loaded assembly. Package 4.18.1 identifies its assembly version as 4.18.0.0, so file checksums, not that version string, identify the dependency.
+
+## Output schema
+
+One detached PSCustomObject per input file, with type name StandaloneFunctions.EmlMessage:
+
+| Property | Meaning |
+|---|---|
+| SourcePath | Absolute source filename |
+| MessageId | Parsed Message-Id, without enclosing angle brackets |
+| Subject | Decoded subject, or null if absent |
+| Date | DateTimeOffset if a usable Date header is parsed; otherwise null |
+| From, To, Cc, Bcc, ReplyTo | Arrays of Name/Address objects; mailbox groups are flattened and group labels omitted |
+| TextBody, HtmlBody | MimeKit-selected decoded body strings, or null; not all alternative body parts |
+| Headers | Ordered Field/Value records, retaining repeated headers; not a byte-preserving raw header copy |
+| Attachments | Metadata for attachment-disposition entities and inline resources: FileName, MimeType, ContentId, IsInline, IsAttachedMessage |
+
+Attachment metadata contains no raw parser objects, streams, decoded byte arrays or extracted files. Inline resources with Content-ID and no disposition are included when not TextPart entities. Attached message/rfc822 parts are identified as attached messages, not recursively normalized into additional output messages. Names are untrusted original metadata, not safe output filenames. No attachment extraction is provided.
+
+No HTML is rendered or sanitized and remote resources are not fetched. No S/MIME/OpenPGP decryption or signature verification is performed. Bodies and metadata remain untrusted message content.
+
+## Errors and limits
+
+Literal input paths avoid wildcard expansion; strings, arrays and FileInfo inputs are supported. Missing files, directories, nonfilesystem inputs, zero-length files, files exceeding MaxFileSizeBytes, dependency mismatches and parser errors terminate the invocation. Earlier results in a multi-file invocation may already have been emitted when a later file fails.
+
+MaxFileSizeBytes defaults to 25 MiB and can be set up to 1 GiB. The check is applied to the opened stream before parsing. It limits input bytes, not total allocations or CPU time; this is not a hostile-input sandbox. MimeKit is intentionally tolerant of imperfect email syntax. Headerless input is rejected, but successful parsing is not full RFC validation and not every malformed multipart message will fail.
+
+The input stream and MimeMessage are disposed in finally; the result remains usable after source deletion. No persistent parsing mode is used.
+
+## Migration from COM
+
+The historical function returned a live CDO.Message and needed Windows ADODB/CDO COM objects. This implementation deliberately changes that contract:
+
+- Use TextBody and HtmlBody instead of CDO.TextBody/HTMLBody assumptions (PowerShell casing is insensitive, but object shape is new).
+- Recipient properties are arrays of records rather than COM address-list strings.
+- Headers is an ordered record array, not the CDO.Fields collection.
+- Attachments supplies metadata, not COM attachment objects or an extraction API.
+- There is no Send method, DataSource, native MIME object or byte-preserving Save operation on the result.
+
+Retain the old implementation on a separate legacy branch if a caller needs its CDO-specific behavior; do not silently mix both contracts. Update consumers and inspect representative real messages before deployment. IT-ToolBox has no equivalent exported function to synchronize here.
+
+## Tests and CI
+
+Tests parse actual synthetic MIME fixtures: encoded UTF-8 headers and base64 body, Latin-1 quoted-printable body, multipart text/HTML, inline resources, binary attachment metadata and attached messages. They also cover repeated headers, literal paths, detached results and file-handle release, empty/malformed/missing/oversized inputs and dependency checks. Network calls are mocked in installer failure/WhatIf tests; no real mailboxes are accessed. CI explicitly installs the pinned dependency before the root test suites on Windows/Linux/macOS. Existing root-suite workflows are updated to do the same so they do not fail for a missing parser dependency.
+
+```powershell
+Import-Module Pester -RequiredVersion 5.7.1
+Invoke-Pester ./Tests -Output Detailed
+```
+
+References:
+https://www.nuget.org/packages/MimeKitLite/4.18.1
+https://github.com/jstedfast/MimeKit
+https://mimekit.net/docs/html/T_MimeKit_MimeMessage.htm
diff --git a/scripts/Install-EmlDependency.ps1 b/scripts/Install-EmlDependency.ps1
new file mode 100644
index 0000000..547cdd0
--- /dev/null
+++ b/scripts/Install-EmlDependency.ps1
@@ -0,0 +1,40 @@
+#Requires -Version 7.4
+[CmdletBinding(SupportsShouldProcess)]
+param (
+    [string]$Destination = (Join-Path $PSScriptRoot '../.eml-dependencies/MimeKitLite/4.18.1')
+)
+
+$ErrorActionPreference = 'Stop'
+$uri = 'https://api.nuget.org/v3-flatcontainer/mimekitlite/4.18.1/mimekitlite.4.18.1.nupkg'
+$expectedHash = '6cc85bb8dfcd3680226082dbf79cd0ac27442ead35a8e75aa1be7b80acc8f28c'
+$destinationPath = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($Destination)
+if (-not $PSCmdlet.ShouldProcess($destinationPath, 'Download and install pinned MimeKitLite 4.18.1 from NuGet')) { return }
+$temp = Join-Path ([System.IO.Path]::GetTempPath()) ('eml-dependency-' + [guid]::NewGuid().ToString('N'))
+try
+{
+    [void][System.IO.Directory]::CreateDirectory($temp)
+    $package = Join-Path $temp 'mimekitlite.nupkg'
+    Invoke-WebRequest -Uri $uri -OutFile $package -ErrorAction Stop
+    if ((Get-FileHash -LiteralPath $package -Algorithm SHA256).Hash -ine $expectedHash)
+    {
+        throw 'MimeKitLite package checksum mismatch; nothing was installed.'
+    }
+    $archive = [System.IO.Compression.ZipFile]::OpenRead($package)
+    try
+    {
+        $entry = $archive.GetEntry('lib/net8.0/MimeKitLite.dll')
+        if ($null -eq $entry) { throw 'Expected net8.0 assembly is absent from package.' }
+        $staged = Join-Path $temp 'MimeKitLite.dll'
+        [System.IO.Compression.ZipFileExtensions]::ExtractToFile($entry, $staged)
+    }
+    finally { $archive.Dispose() }
+    [void][System.IO.Directory]::CreateDirectory($destinationPath)
+    Copy-Item -LiteralPath $staged -Destination (Join-Path $destinationPath 'MimeKitLite.dll') -Force
+    # Retain the original NuGet archive, including its nuspec and upstream licensing metadata.
+    Copy-Item -LiteralPath $package -Destination (Join-Path $destinationPath 'MimeKitLite.4.18.1.nupkg') -Force
+    Write-Output (Join-Path $destinationPath 'MimeKitLite.dll')
+}
+finally
+{
+    if (Test-Path -LiteralPath $temp) { Remove-Item -LiteralPath $temp -Recurse -Force }
+}