diff --git a/.changesets/1792687232-e2151e8b.yaml b/.changesets/1792687232-e2151e8b.yaml
new file mode 100644
index 000000000..16b6d9029
--- /dev/null
+++ b/.changesets/1792687232-e2151e8b.yaml
@@ -0,0 +1,10 @@
+id: 1792687232-e2151e8b
+features:
+    - core
+targets:
+    - cli
+type: fix
+bump: patch
+description: keep a failed temporary directory cleanup in the Windows install script from being reported as an installation failure
+author: AshGodfrey
+date: "2026-10-22"
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 507b517eb..d5b75aece 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -176,10 +176,30 @@ jobs:
     uses: ./.github/workflows/test-cli.yml
     with:
       test-group: "review"
+  test-cli-windows-installer:
+    needs: [detect-targets]
+    if: needs.detect-targets.outputs.run-cli == 'true'
+    name: Test CLI - windows installer (${{ matrix.shell }})
+    timeout-minutes: 15
+    runs-on: windows-latest
+    permissions:
+      contents: "read"
+    strategy:
+      fail-fast: false
+      matrix:
+        shell: [powershell, pwsh]
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+      - name: Test generated Windows installer
+        shell: ${{ matrix.shell }}
+        run: ./scripts/test-windows-installer.ps1
   test-cli:
     if: always() && needs.detect-targets.outputs.run-cli == 'true'
     needs:
       - detect-targets
+      - test-cli-windows-installer
       - test-cli-primary
       - test-cli-secondary
       - test-cli-tertiary
diff --git a/pkg/generate/snapshots/cli_release_go_test.go b/pkg/generate/snapshots/cli_release_go_test.go
index 98469dd1f..2a008002b 100644
--- a/pkg/generate/snapshots/cli_release_go_test.go
+++ b/pkg/generate/snapshots/cli_release_go_test.go
@@ -784,8 +784,13 @@ function Install-CLI {
     }
     finally {
         # Cleanup
-        if (Test-Path $tempDir) {
-            Remove-Item $tempDir -Recurse -Force
+        try {
+            if (Test-Path -LiteralPath $tempDir) {
+                [System.IO.Directory]::Delete($tempDir, $true)
+            }
+        }
+        catch {
+            Write-ColorOutput "Warning: could not remove temporary directory ${tempDir}: $_" -Color Yellow
         }
     }
 }
@@ -1829,8 +1834,13 @@ function Install-CLI {
     }
     finally {
         # Cleanup
-        if (Test-Path $tempDir) {
-            Remove-Item $tempDir -Recurse -Force
+        try {
+            if (Test-Path -LiteralPath $tempDir) {
+                [System.IO.Directory]::Delete($tempDir, $true)
+            }
+        }
+        catch {
+            Write-ColorOutput "Warning: could not remove temporary directory ${tempDir}: $_" -Color Yellow
         }
     }
 }
@@ -2933,8 +2943,13 @@ function Install-CLI {
     }
     finally {
         # Cleanup
-        if (Test-Path $tempDir) {
-            Remove-Item $tempDir -Recurse -Force
+        try {
+            if (Test-Path -LiteralPath $tempDir) {
+                [System.IO.Directory]::Delete($tempDir, $true)
+            }
+        }
+        catch {
+            Write-ColorOutput "Warning: could not remove temporary directory ${tempDir}: $_" -Color Yellow
         }
     }
 }
diff --git a/scripts/test-windows-installer.ps1 b/scripts/test-windows-installer.ps1
new file mode 100644
index 000000000..c95aa9d09
--- /dev/null
+++ b/scripts/test-windows-installer.ps1
@@ -0,0 +1,113 @@
+#Requires -Version 5.1
+<#
+Exercises the generated Windows installer offline: the release download and
+version lookup are replaced by local functions, the installer is run against a
+locally built archive, and the installed binary, download URL, and temporary
+directory cleanup are checked. On Windows a second run holds a file in the
+temporary directory open to confirm a cleanup failure does not fail the install.
+#>
+[CmdletBinding()]
+param(
+    [string]$InstallerPath = (Join-Path $PSScriptRoot '..\zSDKs\sdk-cli\scripts\install.ps1')
+)
+
+$ErrorActionPreference = 'Stop'
+Set-StrictMode -Version Latest
+
+$InstallerPath = (Resolve-Path -LiteralPath $InstallerPath).Path
+$isWindowsHost = [System.Runtime.InteropServices.RuntimeInformation]::IsOSPlatform([System.Runtime.InteropServices.OSPlatform]::Windows)
+
+function Assert-True {
+    param([bool]$Condition, [string]$Message)
+    if (-not $Condition) {
+        throw "Assertion failed: $Message"
+    }
+    Write-Host "ok: $Message"
+}
+
+function New-InstallerSandbox {
+    $root = Join-Path ([System.IO.Path]::GetTempPath()) "installer-test-$([guid]::NewGuid())"
+    foreach ($name in 'temp', 'localappdata', 'install', 'payload') {
+        New-Item -ItemType Directory -Path (Join-Path $root $name) -Force | Out-Null
+    }
+    $binary = Join-Path (Join-Path $root 'payload') 'cli.exe'
+    Set-Content -LiteralPath $binary -Value "stub binary $([guid]::NewGuid())" -NoNewline -Encoding ascii
+    $archive = Join-Path $root 'cli_Windows.zip'
+    Compress-Archive -LiteralPath $binary -DestinationPath $archive
+    [pscustomobject]@{
+        Root       = $root
+        Temp       = Join-Path $root 'temp'
+        InstallDir = Join-Path $root 'install'
+        Binary     = $binary
+        Archive    = $archive
+    }
+}
+
+function Invoke-Installer {
+    param($Sandbox)
+    $env:TEMP = $Sandbox.Temp
+    $env:LOCALAPPDATA = Join-Path $Sandbox.Root 'localappdata'
+    $env:CLI_INSTALL_DIR = $Sandbox.InstallDir
+    $env:CLI_VERSION = 'v0.0.0-test'
+    if (-not $env:PROCESSOR_ARCHITECTURE) {
+        $env:PROCESSOR_ARCHITECTURE = 'AMD64'
+    }
+    $global:InstallerTestArchive = $Sandbox.Archive
+    $global:InstallerTestDownloads = @()
+    & $InstallerPath *>&1 | ForEach-Object { "$_" }
+}
+
+function global:Invoke-RestMethod {
+    throw 'the installer must not look up the latest release when CLI_VERSION is set'
+}
+
+function global:Invoke-WebRequest {
+    param([string]$Uri, [string]$OutFile, [switch]$UseBasicParsing)
+    $global:InstallerTestDownloads += $Uri
+    Copy-Item -LiteralPath $global:InstallerTestArchive -Destination $OutFile
+}
+
+$global:InstallerTestOpenHandle = $null
+function global:Expand-Archive {
+    param([string]$Path, [string]$DestinationPath, [switch]$Force)
+    Microsoft.PowerShell.Archive\Expand-Archive -Path $Path -DestinationPath $DestinationPath -Force:$Force
+    if ($global:InstallerTestHoldExtractedBinary) {
+        $extracted = Join-Path $DestinationPath 'cli.exe'
+        $global:InstallerTestOpenHandle = [System.IO.File]::Open($extracted, 'Open', 'Read', 'Read')
+    }
+}
+
+try {
+    Write-Host '--- install succeeds and cleans up'
+    $global:InstallerTestHoldExtractedBinary = $false
+    $sandbox = New-InstallerSandbox
+    $output = Invoke-Installer $sandbox
+    $installed = Join-Path $sandbox.InstallDir 'cli.exe'
+    Assert-True (Test-Path -LiteralPath $installed) 'binary is copied into CLI_INSTALL_DIR'
+    Assert-True ((Get-Content -LiteralPath $installed -Raw) -eq (Get-Content -LiteralPath $sandbox.Binary -Raw)) 'installed binary matches the archived one'
+    Assert-True ($global:InstallerTestDownloads.Count -eq 1) 'exactly one archive download'
+    Assert-True ($global:InstallerTestDownloads[0] -like '*/releases/download/v0.0.0-test/cli_Windows_*.zip') "download URL names the pinned version: $($global:InstallerTestDownloads[0])"
+    Assert-True (@(Get-ChildItem -LiteralPath $sandbox.Temp -Force).Count -eq 0) 'temporary directory is removed'
+    Assert-True (($output -join "`n") -match 'Installation successful') 'installer reports success'
+
+    if ($isWindowsHost) {
+        Write-Host '--- install succeeds when the temporary directory cannot be removed'
+        $global:InstallerTestHoldExtractedBinary = $true
+        $sandbox = New-InstallerSandbox
+        $output = Invoke-Installer $sandbox
+        $installed = Join-Path $sandbox.InstallDir 'cli.exe'
+        Assert-True (Test-Path -LiteralPath $installed) 'binary is copied despite the held temporary file'
+        Assert-True (($output -join "`n") -match 'Warning: could not remove temporary directory') 'installer warns about the leftover temporary directory'
+        Assert-True (($output -join "`n") -match 'Installation successful') 'installer still reports success'
+        Assert-True (@(Get-ChildItem -LiteralPath $sandbox.Temp -Force).Count -eq 1) 'temporary directory is left in place'
+        $global:InstallerTestOpenHandle.Dispose()
+    }
+    else {
+        Write-Host '--- skipping held-file cleanup case: open files can be deleted on this platform'
+    }
+}
+finally {
+    if ($global:InstallerTestOpenHandle) {
+        $global:InstallerTestOpenHandle.Dispose()
+    }
+}
diff --git a/templates/templates/cli/release/install.ps1.stmpl b/templates/templates/cli/release/install.ps1.stmpl
index 14204893f..e2ec41d12 100644
--- a/templates/templates/cli/release/install.ps1.stmpl
+++ b/templates/templates/cli/release/install.ps1.stmpl
@@ -129,8 +129,13 @@ function Install-CLI {
     }
     finally {
         # Cleanup
-        if (Test-Path $tempDir) {
-            Remove-Item $tempDir -Recurse -Force
+        try {
+            if (Test-Path -LiteralPath $tempDir) {
+                [System.IO.Directory]::Delete($tempDir, $true)
+            }
+        }
+        catch {
+            Write-ColorOutput "Warning: could not remove temporary directory ${tempDir}: $_" -Color Yellow
         }
     }
 }
diff --git a/zSDKs/sdk-cli/.speakeasy/gen.lock b/zSDKs/sdk-cli/.speakeasy/gen.lock
index f9b725c8f..6a4503519 100644
--- a/zSDKs/sdk-cli/.speakeasy/gen.lock
+++ b/zSDKs/sdk-cli/.speakeasy/gen.lock
@@ -662,7 +662,7 @@ trackedFiles:
   internal/usage/schema.go:
     last_write_checksum: sha1:92fdc3775fa21a6a8283bcaa762beac6faf40e57
   scripts/install.ps1:
-    last_write_checksum: sha1:9dcf40ea00ecb8ceda83d5056f57235b43cf658a
+    last_write_checksum: sha1:c03368407505979c2b4498d0d754c7bcda82769a
   scripts/install.sh:
     last_write_checksum: sha1:ba255d220bc830375d4f2bc34a7ca01e0a0a8fe2
   tests/artifact_test.go:
diff --git a/zSDKs/sdk-cli/scripts/install.ps1 b/zSDKs/sdk-cli/scripts/install.ps1
index 909525b12..68551a458 100644
--- a/zSDKs/sdk-cli/scripts/install.ps1
+++ b/zSDKs/sdk-cli/scripts/install.ps1
@@ -129,8 +129,13 @@ function Install-CLI {
     }
     finally {
         # Cleanup
-        if (Test-Path $tempDir) {
-            Remove-Item $tempDir -Recurse -Force
+        try {
+            if (Test-Path -LiteralPath $tempDir) {
+                [System.IO.Directory]::Delete($tempDir, $true)
+            }
+        }
+        catch {
+            Write-ColorOutput "Warning: could not remove temporary directory ${tempDir}: $_" -Color Yellow
         }
     }
 }