diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b55c491..1f65154 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -79,6 +79,11 @@ jobs:
           MACOS_SIGN_PASSWORD: ${{ secrets.MACOS_SIGN_PASSWORD }}
           MACOS_SIGN_TEAM_ID: ${{ vars.MACOS_SIGN_TEAM_ID }}
         run: python scripts/release.py settings
+      - name: Install the pinned Artifact Signing client
+        timeout-minutes: 5
+        if: steps.saved.outputs.restored != 'true'
+        shell: pwsh
+        run: ./scripts/install-signing-client.ps1
       - name: Sign in to Azure with OIDC
         if: steps.saved.outputs.restored != 'true'
         uses: azure/login@8216e11d8cd9b42fe925c852af8e76311ff067ac # v2
@@ -86,7 +91,7 @@ jobs:
           client-id: ${{ vars.AZURE_CLIENT_ID }}
           tenant-id: ${{ vars.AZURE_TENANT_ID }}
           subscription-id: ${{ vars.AZURE_SUBSCRIPTION_ID }}
-      - name: Install the Artifact Signing client and sign the installers
+      - name: Sign the Windows installers
         if: steps.saved.outputs.restored != 'true'
         shell: pwsh
         env:
@@ -94,7 +99,6 @@ jobs:
           ARTIFACT_SIGNING_ACCOUNT_NAME: ${{ vars.ARTIFACT_SIGNING_ACCOUNT_NAME }}
           ARTIFACT_SIGNING_CERTIFICATE_PROFILE_NAME: ${{ vars.ARTIFACT_SIGNING_CERTIFICATE_PROFILE_NAME }}
         run: |
-          Install-Module -Name ArtifactSigning -RequiredVersion 0.1.8 -Scope CurrentUser -Force -Repository PSGallery
           python scripts/release.py prepare-windows
           if ($LASTEXITCODE -ne 0) { throw 'Installer preparation failed.' }
           Get-ChildItem packaging/*.ps1 | ForEach-Object { ./scripts/sign-windows.ps1 -Path $_.FullName }
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 8a4043c..9abea9f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -17,6 +17,16 @@ on:
 permissions:
   contents: read
 jobs:
+  signing-client:
+    runs-on: windows-2025
+    timeout-minutes: 15
+    steps:
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          persist-credentials: false
+      - name: Recover the signing client from a missing package repository
+        shell: pwsh
+        run: ./scripts/test-signing-client.ps1
   saved-release:
     if: github.event_name == 'workflow_dispatch' && inputs.release_run_id != ''
     permissions:
diff --git a/scripts/install-signing-client.ps1 b/scripts/install-signing-client.ps1
new file mode 100644
index 0000000..f922a97
--- /dev/null
+++ b/scripts/install-signing-client.ps1
@@ -0,0 +1,31 @@
+#Requires -Version 7.2
+$ErrorActionPreference = 'Stop'
+Set-StrictMode -Version Latest
+
+for ($attempt = 1; $attempt -le 3; $attempt++) {
+    try {
+        $gallery = @(Get-PSRepository -ErrorAction Stop | Where-Object Name -eq 'PSGallery')
+        if ($gallery.Count -eq 0) {
+            Register-PSRepository -Default -ErrorAction Stop
+            $gallery = @(Get-PSRepository -Name PSGallery -ErrorAction Stop)
+        }
+        if ($gallery.Count -ne 1 -or $gallery[0].SourceLocation.TrimEnd('/') -cne 'https://www.powershellgallery.com/api/v2') {
+            throw [System.Security.SecurityException]::new('PSGallery must use the official HTTPS package source.')
+        }
+        Install-Module -Name ArtifactSigning -RequiredVersion 0.1.8 -Scope CurrentUser -Force -Repository PSGallery -ErrorAction Stop
+        $module = Import-Module ArtifactSigning -RequiredVersion 0.1.8 -Force -PassThru -ErrorAction Stop
+        if ($module.Version -ne [version]'0.1.8' -or -not $module.ExportedCommands.ContainsKey('Invoke-ArtifactSigning')) {
+            throw 'The pinned Artifact Signing client did not load.'
+        }
+        Write-Output 'ArtifactSigning 0.1.8 is installed and ready.'
+        # PackageManagement can leave a native NuGet error code after recovery.
+        # Report success only after the exact module and command have loaded.
+        exit 0
+    } catch [System.Security.SecurityException] {
+        throw
+    } catch {
+        if ($attempt -eq 3) { throw }
+        Write-Warning "Artifact Signing setup attempt $attempt failed: $($_.Exception.Message). Retrying."
+        Start-Sleep -Seconds (5 * $attempt)
+    }
+}
diff --git a/scripts/test-signing-client.ps1 b/scripts/test-signing-client.ps1
new file mode 100644
index 0000000..3f26a30
--- /dev/null
+++ b/scripts/test-signing-client.ps1
@@ -0,0 +1,49 @@
+#Requires -Version 7.2
+$ErrorActionPreference = 'Stop'
+Set-StrictMode -Version Latest
+if ($env:GITHUB_ACTIONS -ne 'true' -or $env:RUNNER_OS -ne 'Windows') {
+    throw 'Run this test only on a disposable Windows Actions runner.'
+}
+$setup = Join-Path $PSScriptRoot 'install-signing-client.ps1'
+
+# Reproduce the failed release with no registered PSGallery, then use the real service.
+if (Get-PSRepository -Name PSGallery -ErrorAction SilentlyContinue) {
+    Unregister-PSRepository -Name PSGallery -ErrorAction Stop
+}
+if (Get-PSRepository -Name PSGallery -ErrorAction SilentlyContinue) { throw 'PSGallery was not removed for the test.' }
+$global:LASTEXITCODE = 23
+& $setup
+if ($LASTEXITCODE -ne 0) { throw 'Successful setup kept a stale native process exit code.' }
+$module = Get-Module -ListAvailable ArtifactSigning | Where-Object Version -eq ([version]'0.1.8')
+if (-not $module) { throw 'The pinned module was not installed.' }
+& $setup
+Write-Output 'Real missing-repository recovery, module import, and repeated setup passed.'
+
+# Check bounded retries without waiting or making extra network requests.
+& {
+    $state = @{ Attempts=0; Sleeps=0; Failures=1; Source='https://www.powershellgallery.com/api/v2' }
+    function Get-PSRepository {
+        [CmdletBinding()] param([string]$Name)
+        [pscustomobject]@{ Name='PSGallery'; SourceLocation=$state.Source }
+    }
+    function Install-Module {
+        [CmdletBinding()] param($Name, $RequiredVersion, $Scope, [switch]$Force, $Repository)
+        if ($Name -ne 'ArtifactSigning' -or $RequiredVersion -ne '0.1.8' -or $Scope -ne 'CurrentUser' -or $Repository -ne 'PSGallery') {
+            throw 'The installer changed its pinned module or repository.'
+        }
+        $state.Attempts++
+        if ($state.Attempts -le $state.Failures) { throw 'Simulated package service failure.' }
+    }
+    function Start-Sleep { param($Seconds) $state.Sleeps++ }
+    & $setup
+    if ($state.Attempts -ne 2 -or $state.Sleeps -ne 1) { throw 'Transient failure recovery failed.' }
+    $state.Attempts=0; $state.Sleeps=0; $state.Failures=3
+    $failed=$false
+    try { & $setup } catch { $failed=$true }
+    if (-not $failed -or $state.Attempts -ne 3 -or $state.Sleeps -ne 2) { throw 'Persistent failures did not stop after three attempts.' }
+    $state.Attempts=0; $state.Sleeps=0; $state.Source='https://packages.example.invalid/api/v2'
+    $failed=$false
+    try { & $setup } catch [System.Security.SecurityException] { $failed=$true }
+    if (-not $failed -or $state.Attempts -ne 0 -or $state.Sleeps -ne 0) { throw 'An unexpected package source was not rejected.' }
+}
+Write-Output 'Retry limits and package source checks passed.'