diff --git a/Start-SPMigrationGUI.ps1 b/Start-SPMigrationGUI.ps1
index 084c91b..b3f570a 100644
--- a/Start-SPMigrationGUI.ps1
+++ b/Start-SPMigrationGUI.ps1
@@ -799,14 +799,15 @@ $script:CurrentMappingMeta = [ordered]@{
     SourceWebUrl = ""
 }
 $script:IsMigrationRunning = $false
-$script:MigrationPowerShell = $null
-$script:MigrationRunspace = $null
-$script:MigrationAsyncResult = $null
-$script:MigrationOutput = $null
+$script:MigrationProcess = $null
+$script:MigrationOutputPath = ""
+$script:MigrationParameterPath = ""
+$script:MigrationWrapperPath = ""
 $script:MigrationTimer = $null
 $script:MigrationStreamPositions = @{}
 $script:MigrationCompletedHandler = $null
 $script:MigrationActionLabel = ""
+$script:LastMigrationErrorMessage = ""
 
 function Get-ObjectPropertyValue {
     param(
@@ -1048,89 +1049,146 @@ function Set-MigrationUiBusy {
 
 function Reset-MigrationStreamPositions {
     $script:MigrationStreamPositions = @{
-        Output = 0
-        Error = 0
-        Warning = 0
-        Verbose = 0
-        Debug = 0
-        Information = 0
+        Output = [long]0
     }
 }
 
-function Write-NewPowerShellRecords {
-    param(
-        $Collection,
-
-        [Parameter(Mandatory = $true)]
-        [string]$PositionKey,
-
-        [ValidateSet("INFO", "WARN", "ERROR")]
-        [string]$Level = "INFO"
+function Get-MigrationHostPath {
+    $windowsPowerShellCandidates = @(
+        (Join-Path -Path $env:WINDIR -ChildPath "Sysnative\WindowsPowerShell\v1.0\powershell.exe"),
+        (Join-Path -Path $env:WINDIR -ChildPath "System32\WindowsPowerShell\v1.0\powershell.exe")
     )
 
-    if ($null -eq $Collection -or -not $script:MigrationStreamPositions.ContainsKey($PositionKey)) {
+    foreach ($candidate in $windowsPowerShellCandidates) {
+        if ([System.IO.File]::Exists($candidate)) {
+            return $candidate
+        }
+    }
+
+    $currentProcessPath = (Get-Process -Id $PID).Path
+    if (-not [string]::IsNullOrWhiteSpace($currentProcessPath) -and [System.IO.File]::Exists($currentProcessPath)) {
+        return $currentProcessPath
+    }
+
+    throw "Kein PowerShell-Host fuer die Migration gefunden."
+}
+
+function Get-SingleQuotedPowerShellLiteral {
+    param(
+        [Parameter(Mandatory = $true)]
+        [string]$Value
+    )
+
+    return "'" + $Value.Replace("'", "''") + "'"
+}
+
+function Write-NewFileRecords {
+    param(
+        [string]$Path,
+
+        [Parameter(Mandatory = $true)]
+        [string]$PositionKey
+    )
+
+    if ([string]::IsNullOrWhiteSpace($Path) -or -not [System.IO.File]::Exists($Path) -or -not $script:MigrationStreamPositions.ContainsKey($PositionKey)) {
         return
     }
 
-    while ($script:MigrationStreamPositions[$PositionKey] -lt $Collection.Count) {
-        $index = [int]$script:MigrationStreamPositions[$PositionKey]
-        $script:MigrationStreamPositions[$PositionKey] = $index + 1
+    $fileStream = $null
+    $reader = $null
+    $text = $null
 
-        try {
-            $record = $Collection[$index]
+    try {
+        $fileStream = [System.IO.File]::Open($Path, [System.IO.FileMode]::Open, [System.IO.FileAccess]::Read, [System.IO.FileShare]::ReadWrite)
+        [void]$fileStream.Seek([long]$script:MigrationStreamPositions[$PositionKey], [System.IO.SeekOrigin]::Begin)
+        $reader = New-Object System.IO.StreamReader($fileStream, [System.Text.UTF8Encoding]::new($false), $true)
+        $text = $reader.ReadToEnd()
+        $script:MigrationStreamPositions[$PositionKey] = $fileStream.Position
+    }
+    catch {
+        return
+    }
+    finally {
+        if ($null -ne $reader) {
+            $reader.Dispose()
         }
-        catch {
-            return
+        elseif ($null -ne $fileStream) {
+            $fileStream.Dispose()
+        }
+    }
+
+    if ([string]::IsNullOrEmpty($text)) {
+        return
+    }
+
+    foreach ($line in ($text -split "`r?`n")) {
+        if ([string]::IsNullOrWhiteSpace($line)) {
+            continue
         }
 
-        $text = Convert-RecordToLogText -Record $record
-        if (-not [string]::IsNullOrWhiteSpace($text)) {
-            Write-UILog -Message $text -Level $Level
+        $level = "INFO"
+        $message = $line
+        if ($line -match '^\[(INFO|WARN|ERROR)\]\s*(.*)$') {
+            $level = $matches[1]
+            $message = $matches[2]
         }
+
+        if ([string]::IsNullOrWhiteSpace($message)) {
+            continue
+        }
+
+        if ($level -eq "ERROR") {
+            $script:LastMigrationErrorMessage = $message
+        }
+
+        Write-UILog -Message $message -Level $level
     }
 }
 
-function Write-NewMigrationPowerShellRecords {
-    if ($null -eq $script:MigrationPowerShell) {
-        return
-    }
-
-    Write-NewPowerShellRecords -Collection $script:MigrationOutput -PositionKey "Output" -Level "INFO"
-    Write-NewPowerShellRecords -Collection $script:MigrationPowerShell.Streams.Warning -PositionKey "Warning" -Level "WARN"
-    Write-NewPowerShellRecords -Collection $script:MigrationPowerShell.Streams.Error -PositionKey "Error" -Level "ERROR"
-    Write-NewPowerShellRecords -Collection $script:MigrationPowerShell.Streams.Verbose -PositionKey "Verbose" -Level "INFO"
-    Write-NewPowerShellRecords -Collection $script:MigrationPowerShell.Streams.Debug -PositionKey "Debug" -Level "INFO"
-    Write-NewPowerShellRecords -Collection $script:MigrationPowerShell.Streams.Information -PositionKey "Information" -Level "INFO"
+function Write-NewMigrationProcessRecords {
+    Write-NewFileRecords -Path $script:MigrationOutputPath -PositionKey "Output"
 }
 
 function Clear-MigrationRunState {
-    if ($null -ne $script:MigrationPowerShell) {
-        $script:MigrationPowerShell.Dispose()
-    }
-
-    if ($null -ne $script:MigrationRunspace) {
-        $script:MigrationRunspace.Dispose()
-    }
-
-    if ($null -ne $script:MigrationOutput) {
+    if ($null -ne $script:MigrationProcess) {
         try {
-            $script:MigrationOutput.Dispose()
+            if (-not $script:MigrationProcess.HasExited) {
+                $script:MigrationProcess.Kill()
+                $script:MigrationProcess.WaitForExit()
+            }
+        }
+        catch {
+        }
+
+        $script:MigrationProcess.Dispose()
+    }
+
+    foreach ($path in @($script:MigrationWrapperPath, $script:MigrationParameterPath, $script:MigrationOutputPath)) {
+        if ([string]::IsNullOrWhiteSpace($path)) {
+            continue
+        }
+
+        try {
+            if (Test-Path -LiteralPath $path) {
+                Remove-Item -LiteralPath $path -Force -ErrorAction Stop
+            }
         }
         catch {
         }
     }
 
-    $script:MigrationPowerShell = $null
-    $script:MigrationRunspace = $null
-    $script:MigrationAsyncResult = $null
-    $script:MigrationOutput = $null
+    $script:MigrationProcess = $null
+    $script:MigrationOutputPath = ""
+    $script:MigrationParameterPath = ""
+    $script:MigrationWrapperPath = ""
     $script:MigrationCompletedHandler = $null
     $script:MigrationActionLabel = ""
+    $script:LastMigrationErrorMessage = ""
     Reset-MigrationStreamPositions
 }
 
 function Complete-MigrationScriptAsync {
-    if ($null -eq $script:MigrationPowerShell -or $null -eq $script:MigrationAsyncResult) {
+    if ($null -eq $script:MigrationProcess) {
         return
     }
 
@@ -1139,17 +1197,23 @@ function Complete-MigrationScriptAsync {
     $success = $false
     $errorMessage = $null
 
-    Write-NewMigrationPowerShellRecords
+    Write-NewMigrationProcessRecords
+
+    if (-not $script:MigrationProcess.HasExited) {
+        return
+    }
 
     try {
-        [void]$script:MigrationPowerShell.EndInvoke($script:MigrationAsyncResult)
-        Write-NewMigrationPowerShellRecords
-        $success = $true
-    }
-    catch {
-        Write-NewMigrationPowerShellRecords
-        $errorMessage = $_.Exception.Message
-        Write-UILog -Message $errorMessage -Level "ERROR"
+        if ($script:MigrationProcess.ExitCode -eq 0) {
+            $success = $true
+        }
+        else {
+            $errorMessage = $script:LastMigrationErrorMessage
+            if ([string]::IsNullOrWhiteSpace($errorMessage)) {
+                $errorMessage = "Der Migrationsprozess wurde mit ExitCode $($script:MigrationProcess.ExitCode) beendet."
+                Write-UILog -Message $errorMessage -Level "ERROR"
+            }
+        }
     }
     finally {
         Clear-MigrationRunState
@@ -1182,9 +1246,9 @@ function Ensure-MigrationTimer {
     $script:MigrationTimer = New-Object System.Windows.Forms.Timer
     $script:MigrationTimer.Interval = 250
     $script:MigrationTimer.Add_Tick({
-        Write-NewMigrationPowerShellRecords
+        Write-NewMigrationProcessRecords
 
-        if ($null -eq $script:MigrationAsyncResult -or -not $script:MigrationAsyncResult.IsCompleted) {
+        if ($null -eq $script:MigrationProcess -or -not $script:MigrationProcess.HasExited) {
             return
         }
 
@@ -1213,28 +1277,99 @@ function Invoke-MigrationScript {
     }
 
     Reset-MigrationStreamPositions
-    $script:MigrationRunspace = [runspacefactory]::CreateRunspace()
-    $script:MigrationRunspace.ApartmentState = [System.Threading.ApartmentState]::STA
-    $script:MigrationRunspace.ThreadOptions = [System.Management.Automation.Runspaces.PSThreadOptions]::ReuseThread
-    $script:MigrationRunspace.Open()
-
-    $script:MigrationPowerShell = [powershell]::Create()
-    $script:MigrationPowerShell.Runspace = $script:MigrationRunspace
-    $script:MigrationOutput = [System.Management.Automation.PSDataCollection[psobject]]::new()
+    $script:LastMigrationErrorMessage = ""
     $script:MigrationCompletedHandler = $OnCompleted
     $script:MigrationActionLabel = $ActionLabel
 
+    $tempDirectory = Join-Path -Path ([System.IO.Path]::GetTempPath()) -ChildPath "StartSPMigrationGui"
+    if (-not [System.IO.Directory]::Exists($tempDirectory)) {
+        [System.IO.Directory]::CreateDirectory($tempDirectory) | Out-Null
+    }
+
+    $runId = [guid]::NewGuid().ToString("N")
+    $parameterPath = Join-Path -Path $tempDirectory -ChildPath ("migration-parameters-{0}.clixml" -f $runId)
+    $outputPath = Join-Path -Path $tempDirectory -ChildPath ("migration-output-{0}.log" -f $runId)
+    $wrapperPath = Join-Path -Path $tempDirectory -ChildPath ("migration-runner-{0}.ps1" -f $runId)
+
     try {
-        [void]$script:MigrationPowerShell.AddCommand($script:MigrationScriptPath)
-        [void]$script:MigrationPowerShell.AddParameters($Parameters)
+        Export-Clixml -LiteralPath $parameterPath -InputObject $Parameters
+        [System.IO.File]::WriteAllText($outputPath, "", [System.Text.UTF8Encoding]::new($false))
+
+        $wrapperContent = @"
+`$ErrorActionPreference = 'Stop'
+`$parameters = Import-Clixml -LiteralPath $(Get-SingleQuotedPowerShellLiteral -Value $parameterPath)
+`$logPath = $(Get-SingleQuotedPowerShellLiteral -Value $outputPath)
+`$logDirectory = [System.IO.Path]::GetDirectoryName(`$logPath)
+if (-not [System.IO.Directory]::Exists(`$logDirectory)) {
+    [System.IO.Directory]::CreateDirectory(`$logDirectory) | Out-Null
+}
+
+`$script:LogWriter = [System.IO.StreamWriter]::new(`$logPath, `$true, [System.Text.UTF8Encoding]::new(`$false))
+`$script:LogWriter.AutoFlush = `$true
+
+function Write-RunnerLog {
+    param(
+        [Parameter(Mandatory = `$true)]
+        [ValidateSet('INFO', 'WARN', 'ERROR')]
+        [string]`$Level,
+
+        [string]`$Message
+    )
+
+    if ([string]::IsNullOrWhiteSpace(`$Message)) {
+        return
+    }
+
+    `$script:LogWriter.WriteLine(('[{0}] {1}' -f `$Level, `$Message))
+}
+
+try {
+    & $(Get-SingleQuotedPowerShellLiteral -Value $script:MigrationScriptPath) @parameters *>&1 | ForEach-Object {
+        `$level = switch (`$_.GetType().FullName) {
+            'System.Management.Automation.ErrorRecord' { 'ERROR'; break }
+            'System.Management.Automation.WarningRecord' { 'WARN'; break }
+            default { 'INFO' }
+        }
+
+        Write-RunnerLog -Level `$level -Message ([string]`$_)
+    }
+
+    exit 0
+}
+catch {
+    Write-RunnerLog -Level 'ERROR' -Message `$_.Exception.Message
+    exit 1
+}
+finally {
+    if (`$null -ne `$script:LogWriter) {
+        `$script:LogWriter.Dispose()
+    }
+}
+"@
+
+        Set-Content -LiteralPath $wrapperPath -Value $wrapperContent -Encoding UTF8
+
+        $hostPath = Get-MigrationHostPath
+        $processStartInfo = New-Object System.Diagnostics.ProcessStartInfo
+        $processStartInfo.FileName = $hostPath
+        $processStartInfo.Arguments = ('-NoProfile -ExecutionPolicy Bypass -File "{0}"' -f $wrapperPath.Replace('"', '""'))
+        $processStartInfo.WorkingDirectory = Split-Path -Path $script:MigrationScriptPath -Parent
+        $processStartInfo.UseShellExecute = $false
+        $processStartInfo.CreateNoWindow = $true
+
+        $script:MigrationProcess = New-Object System.Diagnostics.Process
+        $script:MigrationProcess.StartInfo = $processStartInfo
+        if (-not $script:MigrationProcess.Start()) {
+            throw "Der Migrationsprozess konnte nicht gestartet werden."
+        }
+
+        $script:MigrationOutputPath = $outputPath
+        $script:MigrationParameterPath = $parameterPath
+        $script:MigrationWrapperPath = $wrapperPath
 
         Set-MigrationUiBusy -IsBusy $true
         Write-UILog -Message ("Starte {0}..." -f $ActionLabel)
 
-        $inputCollection = [System.Management.Automation.PSDataCollection[psobject]]::new()
-        $inputCollection.Complete()
-        $script:MigrationAsyncResult = $script:MigrationPowerShell.BeginInvoke($inputCollection, $script:MigrationOutput)
-
         Ensure-MigrationTimer
         $script:MigrationTimer.Start()
     }
@@ -2787,3 +2922,4 @@ if ($NoGui.IsPresent) {
 }
 
 $formBuilder.Show()
+