diff --git a/eng/Version.Details.props b/eng/Version.Details.props
index 8198264a4a0..c4c5cabdb3a 100644
--- a/eng/Version.Details.props
+++ b/eng/Version.Details.props
@@ -8,10 +8,10 @@ This file should be imported by eng/Versions.props
     <!-- dotnet-arcade dependencies -->
     <MicrosoftDotNetArcadeSdkPackageVersion>10.0.0-beta.26301.2</MicrosoftDotNetArcadeSdkPackageVersion>
     <!-- dotnet-msbuild dependencies -->
-    <MicrosoftBuildPackageVersion>18.8.0-preview-26275-09</MicrosoftBuildPackageVersion>
-    <MicrosoftBuildFrameworkPackageVersion>18.8.0-preview-26275-09</MicrosoftBuildFrameworkPackageVersion>
-    <MicrosoftBuildTasksCorePackageVersion>18.8.0-preview-26275-09</MicrosoftBuildTasksCorePackageVersion>
-    <MicrosoftBuildUtilitiesCorePackageVersion>18.8.0-preview-26275-09</MicrosoftBuildUtilitiesCorePackageVersion>
+    <MicrosoftBuildPackageVersion>18.9.0-preview-26302-08</MicrosoftBuildPackageVersion>
+    <MicrosoftBuildFrameworkPackageVersion>18.9.0-preview-26302-08</MicrosoftBuildFrameworkPackageVersion>
+    <MicrosoftBuildTasksCorePackageVersion>18.9.0-preview-26302-08</MicrosoftBuildTasksCorePackageVersion>
+    <MicrosoftBuildUtilitiesCorePackageVersion>18.9.0-preview-26302-08</MicrosoftBuildUtilitiesCorePackageVersion>
     <!-- dotnet-optimization dependencies -->
     <optimizationlinuxarm64MIBCRuntimePackageVersion>1.0.0-prerelease.26276.2</optimizationlinuxarm64MIBCRuntimePackageVersion>
     <optimizationlinuxx64MIBCRuntimePackageVersion>1.0.0-prerelease.26276.2</optimizationlinuxx64MIBCRuntimePackageVersion>
diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index 78884c3639f..456ca205af7 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -2,21 +2,21 @@
 <Dependencies>
   <Source Uri="https://github.com/dotnet/dotnet" Mapping="fsharp" Sha="d64191f29ec9042e2696d8b7d8326c4bd10ba268" BarId="313368" />
   <ProductDependencies>
-    <Dependency Name="Microsoft.Build" Version="18.8.0-preview-26275-09">
+    <Dependency Name="Microsoft.Build" Version="18.9.0-preview-26302-08">
       <Uri>https://github.com/dotnet/msbuild</Uri>
-      <Sha>4ea8215937724cd480a29c30187195b5cbda7486</Sha>
+      <Sha>de9a0e9765117fc68117bb002f58066eedaee3d4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Build.Framework" Version="18.8.0-preview-26275-09">
+    <Dependency Name="Microsoft.Build.Framework" Version="18.9.0-preview-26302-08">
       <Uri>https://github.com/dotnet/msbuild</Uri>
-      <Sha>4ea8215937724cd480a29c30187195b5cbda7486</Sha>
+      <Sha>de9a0e9765117fc68117bb002f58066eedaee3d4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Build.Tasks.Core" Version="18.8.0-preview-26275-09">
+    <Dependency Name="Microsoft.Build.Tasks.Core" Version="18.9.0-preview-26302-08">
       <Uri>https://github.com/dotnet/msbuild</Uri>
-      <Sha>4ea8215937724cd480a29c30187195b5cbda7486</Sha>
+      <Sha>de9a0e9765117fc68117bb002f58066eedaee3d4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Build.Utilities.Core" Version="18.8.0-preview-26275-09">
+    <Dependency Name="Microsoft.Build.Utilities.Core" Version="18.9.0-preview-26302-08">
       <Uri>https://github.com/dotnet/msbuild</Uri>
-      <Sha>4ea8215937724cd480a29c30187195b5cbda7486</Sha>
+      <Sha>de9a0e9765117fc68117bb002f58066eedaee3d4</Sha>
     </Dependency>
     <Dependency Name="Microsoft.CodeAnalysis" Version="5.9.0-1.26302.3">
       <Uri>https://github.com/dotnet/roslyn</Uri>
diff --git a/eng/templates/regression-test-jobs.yml b/eng/templates/regression-test-jobs.yml
index 9b50f376fe9..16da81059c2 100644
--- a/eng/templates/regression-test-jobs.yml
+++ b/eng/templates/regression-test-jobs.yml
@@ -115,6 +115,25 @@ jobs:
         version: '9.0.x'
         installationPath: $(Pipeline.Workspace)/TestRepo/.dotnet
 
+    - pwsh: |
+        # Clean leftover SDK extraction directories in agent temp to prevent
+        # UseDotNet@2 "file already exists" errors when installing multiple SDKs sequentially.
+        # The task extracts to a temp folder before moving to installationPath, but doesn't
+        # always clean up between runs on the same agent.
+        $tempDir = $env:AGENT_TEMPDIRECTORY
+        if ($tempDir -and (Test-Path $tempDir)) {
+          Get-ChildItem $tempDir -Directory -ErrorAction SilentlyContinue |
+            Where-Object {
+              (Test-Path (Join-Path $_.FullName "dotnet.exe")) -and
+              ((Test-Path (Join-Path $_.FullName "sdk")) -or (Test-Path (Join-Path $_.FullName "host")) -or (Test-Path (Join-Path $_.FullName "shared")))
+            } |
+            ForEach-Object {
+              Write-Host "Removing leftover dotnet extraction dir: $($_.FullName)"
+              Remove-Item $_.FullName -Recurse -Force -ErrorAction Stop
+            }
+        }
+      displayName: Clean UseDotNet temp extraction directories for ${{ item.displayName }}
+
     - task: UseDotNet@2
       displayName:  Install .NET SDK 10.0.100 for ${{ item.displayName }}
       inputs: