diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b7e8ae501..e65246569 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -52,6 +52,10 @@ jobs:
             java: 17
             distribution: temurin
             jobtype: 10
+          - os: windows-latest
+            java: 17
+            distribution: zulu
+            jobtype: 12
     runs-on: ${{ matrix.os }}
     timeout-minutes: 25
     env:
@@ -192,3 +196,8 @@ jobs:
           find **/src/main/contraband-scala -name "*.scala" -delete || true
           sbt generateContrabands
           git diff --exit-code
+      - name: Build and test (12)
+        if: ${{ matrix.jobtype == 12 }}
+        shell: bash
+        run: |
+          ./sbt -v "scripted cache/*"
\ No newline at end of file
diff --git a/sbt-app/src/sbt-test/cache/basic/build.sbt b/sbt-app/src/sbt-test/cache/basic/build.sbt
index 30f1f6298..34c378d69 100644
--- a/sbt-app/src/sbt-test/cache/basic/build.sbt
+++ b/sbt-app/src/sbt-test/cache/basic/build.sbt
@@ -9,15 +9,15 @@ val checkMapN1 = taskKey[Unit]("")
 Global / localCacheDirectory := baseDirectory.value / "diskcache"
 
 pure1 := {
-  val output = StringVirtualFile1("target/out/a.txt", "foo")
+  val output = StringVirtualFile1("${OUT}/a.txt", "foo")
   Def.declareOutput(output)
   ()
 }
 
 map1 := {
   pure1.value
-  val output1 = StringVirtualFile1("target/out/b1.txt", "foo")
-  val output2 = StringVirtualFile1("target/out/b2.txt", "foo")
+  val output1 = StringVirtualFile1("${OUT}/b1.txt", "foo")
+  val output2 = StringVirtualFile1("${OUT}/b2.txt", "foo")
   Def.declareOutput(output1)
   Def.declareOutput(output2)
   "something"
@@ -26,7 +26,7 @@ map1 := {
 mapN1 := {
   pure1.value
   map1.value
-  val output = StringVirtualFile1("target/out/c.txt", "foo")
+  val output = StringVirtualFile1("${OUT}/c.txt", "foo")
   Def.declareOutput(output)
   ()
 }
diff --git a/sbt-app/src/sbt-test/cache/optout/build.sbt b/sbt-app/src/sbt-test/cache/optout/build.sbt
index f300a13a9..d71451ada 100644
--- a/sbt-app/src/sbt-test/cache/optout/build.sbt
+++ b/sbt-app/src/sbt-test/cache/optout/build.sbt
@@ -9,8 +9,8 @@ aa := Def.uncached(A())
 // This tests that aa is opted out from caching
 map1 := {
   aa.value
-  val output1 = StringVirtualFile1("target/out/b1.txt", "foo")
-  val output2 = StringVirtualFile1("target/out/b2.txt", "foo")
+  val output1 = StringVirtualFile1("${OUT}/b1.txt", "foo")
+  val output2 = StringVirtualFile1("${OUT}/b2.txt", "foo")
   Def.declareOutput(output1)
   Def.declareOutput(output2)
   "something"
@@ -19,7 +19,7 @@ map1 := {
 mapN1 := {
   aa.value
   map1.value
-  val output = StringVirtualFile1("target/out/c.txt", "foo")
+  val output = StringVirtualFile1("${OUT}/c.txt", "foo")
   Def.declareOutput(output)
   ()
 }
diff --git a/sbt-app/src/sbt-test/cache/transitive/build.sbt b/sbt-app/src/sbt-test/cache/transitive/build.sbt
index f94a6d203..1d65f7e00 100644
--- a/sbt-app/src/sbt-test/cache/transitive/build.sbt
+++ b/sbt-app/src/sbt-test/cache/transitive/build.sbt
@@ -7,14 +7,14 @@ val checkTask = taskKey[Unit]("Check that files exist")
 Global / localCacheDirectory := baseDirectory.value / "diskcache"
 
 task2 := {
-  val output = StringVirtualFile1("target/out/t2.txt", "task2 output")
+  val output = StringVirtualFile1("${OUT}/t2.txt", "task2 output")
   Def.declareOutput(output)
   ()
 }
 
 task1 := {
   task2.value
-  val output = StringVirtualFile1("target/out/t1.txt", "task1 output")
+  val output = StringVirtualFile1("${OUT}/t1.txt", "task1 output")
   Def.declareOutput(output)
   ()
 }
diff --git a/util-cache/src/main/scala/sbt/util/ActionCache.scala b/util-cache/src/main/scala/sbt/util/ActionCache.scala
index 506f6ee73..f7331a469 100644
--- a/util-cache/src/main/scala/sbt/util/ActionCache.scala
+++ b/util-cache/src/main/scala/sbt/util/ActionCache.scala
@@ -82,8 +82,16 @@ object ActionCache:
             cacheEventLog.append(ActionCacheEvent.Error)
             throw e
       val json = Converter.toJsonUnsafe(result)
+      val normalizedOutputDir = outputDirectory.toAbsolutePath.normalize()
       val uncacheableOutputs =
-        outputs.filter(f => !fileConverter.toPath(f).toAbsolutePath.startsWith(outputDirectory))
+        outputs.filter(f =>
+          f match
+            case vf if vf.id.endsWith(ActionCache.dirZipExt) =>
+              false
+            case _ =>
+              val outputPath = fileConverter.toPath(f).toAbsolutePath.normalize()
+              !outputPath.startsWith(normalizedOutputDir)
+        )
       if uncacheableOutputs.nonEmpty then
         cacheEventLog.append(ActionCacheEvent.Error)
         logger.error(
diff --git a/util-cache/src/main/scala/sbt/util/ActionCacheStore.scala b/util-cache/src/main/scala/sbt/util/ActionCacheStore.scala
index 1f16ce959..733aa32e7 100644
--- a/util-cache/src/main/scala/sbt/util/ActionCacheStore.scala
+++ b/util-cache/src/main/scala/sbt/util/ActionCacheStore.scala
@@ -290,7 +290,7 @@ class DiskActionCacheStore(base: Path, converter: FileConverter) extends Abstrac
     // On Windows, the program has be running under the Administrator privileges or the
     // user enable Developer Mode on Windows 10+ to create symbolic links.
     def writeFileAndNotify(outPath: Path): Path =
-      IO.createDirectory(outPath.getParent().toFile())
+      Option(outPath.getParent()).foreach(parent => IO.createDirectory(parent.toFile()))
       val result = Retry:
         if Files.exists(outPath) then IO.delete(outPath.toFile())
         if symlinkSupported.get() && Files.exists(casFile) then
@@ -312,7 +312,10 @@ class DiskActionCacheStore(base: Path, converter: FileConverter) extends Abstrac
         else copyFile(outPath)
       afterFileWrite(ref, result, outputDirectory)
       result
-    converter.toPath(ref) match
+    val resolvedPath = converter.toPath(ref) match
+      case p if p.isAbsolute => p
+      case p                 => outputDirectory.resolve(p)
+    resolvedPath match
       case p if !Files.exists(p) =>
         // println(s"- syncFile: $p does not exist")
         writeFileAndNotify(p)