diff --git a/pester/install-rendering.Tests.ps1 b/pester/install-rendering.Tests.ps1
index 0b4a5430..a264e732 100644
--- a/pester/install-rendering.Tests.ps1
+++ b/pester/install-rendering.Tests.ps1
@@ -33,6 +33,90 @@ Describe "Install app rendering startup contract" {
         $renderScript | Should -Not -Match '& \$renderCategory'
     }
 
+    It "drains queued app batches on the WPF dispatcher without timer scope errors" {
+        Add-Type -AssemblyName WindowsBase
+        . (Join-Path $script:repoRoot "functions\private\Start-WinUtilInstallAppRendering.ps1")
+
+        $previousSync = Get-Variable -Name sync -Scope Global -ErrorAction SilentlyContinue
+        $previousInitializeAppEntry = Get-Item -Path Function:\Initialize-InstallAppEntry -ErrorAction SilentlyContinue
+        $previousSearch = Get-Item -Path Function:\Find-AppsByNameOrDescription -ErrorAction SilentlyContinue
+        $previousCheckpoint = Get-Item -Path Function:\Write-WinUtilPerformanceCheckpoint -ErrorAction SilentlyContinue
+        $errorCountBefore = $global:Error.Count
+
+        try {
+            $global:sync = [Hashtable]::Synchronized(@{})
+            $global:sync.currentTab = "Install"
+            $global:sync.SearchBar = [pscustomobject]@{ Text = "" }
+            $global:sync.Form = [pscustomobject]@{ Dispatcher = [System.Windows.Threading.Dispatcher]::CurrentDispatcher }
+            $global:sync.InstallAppRenderQueue = [System.Collections.Queue]::new()
+
+            $renderedApps = [System.Collections.Generic.List[string]]::new()
+            $checkpoints = [System.Collections.Generic.List[string]]::new()
+
+            function global:Initialize-InstallAppEntry {
+                param($TargetElement, $AppKey)
+                $renderedApps.Add($AppKey)
+                return "entry:$AppKey"
+            }
+
+            function global:Find-AppsByNameOrDescription {
+                param($SearchString)
+                throw "Search should not run for an empty search box in this test."
+            }
+
+            function global:Write-WinUtilPerformanceCheckpoint {
+                param([string]$Name)
+                $checkpoints.Add($Name)
+            }
+
+            $global:sync.InstallAppRenderQueue.Enqueue([pscustomobject]@{ TargetElement = [pscustomobject]@{}; AppKeys = @("AppA", "AppB") })
+            $global:sync.InstallAppRenderQueue.Enqueue([pscustomobject]@{ TargetElement = [pscustomobject]@{}; AppKeys = @("AppC") })
+
+            $frame = New-Object System.Windows.Threading.DispatcherFrame
+            $timeout = [System.Diagnostics.Stopwatch]::StartNew()
+            Start-WinUtilInstallAppRendering
+
+            $closeTimer = New-Object System.Windows.Threading.DispatcherTimer
+            $closeTimer.Interval = [TimeSpan]::FromMilliseconds(25)
+            $closeTimer.Add_Tick({
+                param($sender)
+                $timer = [System.Windows.Threading.DispatcherTimer]$sender
+
+                if ($global:sync.InstallAppEntriesRendered -or $timeout.Elapsed.TotalSeconds -gt 5) {
+                    $timer.Stop()
+                    $frame.Continue = $false
+                }
+            })
+            $closeTimer.Start()
+
+            [System.Windows.Threading.Dispatcher]::PushFrame($frame)
+
+            $global:sync.InstallAppEntriesRendered | Should -BeTrue
+            $global:sync.InstallAppRenderQueue.Count | Should -Be 0
+            @($renderedApps) | Should -Be @("AppA", "AppB", "AppC")
+            @($checkpoints) | Should -Contain "Install app entries rendered"
+            $global:Error.Count | Should -Be $errorCountBefore
+        } finally {
+            if ($previousSync) {
+                Set-Variable -Name sync -Value $previousSync.Value -Scope Global
+            } else {
+                Remove-Variable -Name sync -Scope Global -ErrorAction SilentlyContinue
+            }
+
+            foreach ($functionBackup in @(
+                    @{ Name = "Initialize-InstallAppEntry"; Backup = $previousInitializeAppEntry },
+                    @{ Name = "Find-AppsByNameOrDescription"; Backup = $previousSearch },
+                    @{ Name = "Write-WinUtilPerformanceCheckpoint"; Backup = $previousCheckpoint }
+                )) {
+                if ($functionBackup.Backup) {
+                    Set-Item -Path "Function:\$($functionBackup.Name)" -Value $functionBackup.Backup.ScriptBlock
+                } else {
+                    Remove-Item -Path "Function:\$($functionBackup.Name)" -ErrorAction SilentlyContinue
+                }
+            }
+        }
+    }
+
     It "keeps app-entry metadata lookup independent from the old caller scope" {
         $entryScript = Get-Content -Path (Join-Path $script:repoRoot "functions\private\Initialize-InstallAppEntry.ps1") -Raw