diff --git a/build-windows.ps1 b/build-windows.ps1
index 198b311..80f884e 100644
--- a/build-windows.ps1
+++ b/build-windows.ps1
@@ -96,6 +96,13 @@ Expand-Archive -Path $srcZip -DestinationPath $srcDir -Force
 $repoDir = (Get-ChildItem $srcDir -Directory | Select-Object -First 1).FullName
 
 Write-Host "      Kompiliere upterm (GOTOOLCHAIN=auto, laedt ggf. neueres Go)..."
+# Kurze Temp-Pfade setzen (langer Benutzerpfad kann Windows-Fehler 87 ausloesen)
+New-Item -ItemType Directory -Force -Path "C:\GoTemp"  | Out-Null
+New-Item -ItemType Directory -Force -Path "C:\GoCache" | Out-Null
+$env:TEMP      = "C:\GoTemp"
+$env:TMP       = "C:\GoTemp"
+$env:GOCACHE   = "C:\GoCache"
+$env:GOTMPDIR  = "C:\GoTemp"
 Push-Location $repoDir
 $env:GOTOOLCHAIN = "auto"
 & $goExe build -o "$env:GOPATH\bin\upterm.exe" ./cmd/upterm 2>&1 | ForEach-Object { Write-Host "      $_" }