diff --git a/internal/util-core/src/main/scala/sbt/internal/util/Util.scala b/internal/util-core/src/main/scala/sbt/internal/util/Util.scala
index e5024f215..7e6d6d5a7 100644
--- a/internal/util-core/src/main/scala/sbt/internal/util/Util.scala
+++ b/internal/util-core/src/main/scala/sbt/internal/util/Util.scala
@@ -8,12 +8,13 @@
 
 package sbt.internal.util
 
-import java.nio.file.{ Path, Paths }
+import java.nio.file.{ Files, Path, Paths }
 import java.util.Locale
 
 import scala.collection.concurrent.TrieMap
 import scala.reflect.Selectable.reflectiveSelectable
 import scala.util.Properties
+import scala.util.control.NonFatal
 
 object Util:
   def makeList[T](size: Int, value: T): List[T] = List.fill(size)(value)
@@ -77,6 +78,10 @@ object Util:
 
   lazy val isEmacs: Boolean = sys.env.contains("INSIDE_EMACS")
 
+  def isApfs(path: Path): Boolean =
+    try Files.getFileStore(path).`type`().equalsIgnoreCase("apfs")
+    catch case NonFatal(_) => false
+
   def nil[A]: List[A] = List.empty[A]
   def nilSeq[A]: Seq[A] = Seq.empty[A]
   def none[A]: Option[A] = (None: Option[A])
diff --git a/util-cache/src/main/scala/sbt/util/ActionCacheStore.scala b/util-cache/src/main/scala/sbt/util/ActionCacheStore.scala
index 0f7975646..ff0ab8783 100644
--- a/util-cache/src/main/scala/sbt/util/ActionCacheStore.scala
+++ b/util-cache/src/main/scala/sbt/util/ActionCacheStore.scala
@@ -196,7 +196,9 @@ case class DiskActionCacheStore(base: Path, converter: FileConverter)
     dir
   }
 
-  private val symlinkSupported: AtomicBoolean = AtomicBoolean(true)
+  // Files.copy clones on APFS, so a real file costs no extra disk while sparing every later
+  // directory walk the CAS inode lookup that resolving a symlink pays.
+  private lazy val symlinkSupported: AtomicBoolean = AtomicBoolean(!Util.isApfs(casBase))
 
   override def storeName: String = "disk"
 
diff --git a/util-cache/src/test/scala/sbt/util/ActionCacheTest.scala b/util-cache/src/test/scala/sbt/util/ActionCacheTest.scala
index c0c6fe9e2..8e9165356 100644
--- a/util-cache/src/test/scala/sbt/util/ActionCacheTest.scala
+++ b/util-cache/src/test/scala/sbt/util/ActionCacheTest.scala
@@ -8,6 +8,7 @@ import java.util.concurrent.{ CyclicBarrier, ExecutorService, Executors, TimeUni
 
 import sbt.internal.util.CacheEventLog
 import sbt.internal.util.StringVirtualFile1
+import sbt.internal.util.Util
 import sbt.io.IO
 import sbt.io.syntax.*
 import verify.BasicTestSuite
@@ -140,6 +141,7 @@ object ActionCacheTest extends BasicTestSuite:
         cache.syncBlobs(refs, outputDirectory)
         assert((dir / "a.txt").exists, "a.txt not re-extracted after the directory was deleted")
         assert((dir / "b.txt").exists, "b.txt not re-extracted after the directory was deleted")
+        assertMaterialized(cache, (dir / "a.txt").toPath)
 
   test("Disk cache does not re-extract a dirzip whose archive digest already matches"):
     withDiskCache: cache =>
@@ -160,7 +162,7 @@ object ActionCacheTest extends BasicTestSuite:
         cache.syncBlobs(refs, outputDirectory)
         assert(IO.read(dir / "a.txt") == "diverged")
 
-  test("Disk cache relinks a digest-matching dirzip to the CAS"):
+  test("Disk cache materializes a digest-matching dirzip from the CAS"):
     withDiskCache: cache =>
       IO.withTemporaryDirectory: tempDir =>
         val outputDirectory = tempDir.toPath()
@@ -176,7 +178,7 @@ object ActionCacheTest extends BasicTestSuite:
         assert(!Files.isSymbolicLink(zipPath), "packageDirectory should leave a regular file")
 
         cache.syncBlobs(refs, outputDirectory)
-        assert(Files.isSymbolicLink(zipPath), "digest-matching archive was not relinked to the CAS")
+        assertMaterialized(cache, zipPath)
 
   test("Disk cache re-extracts a dirzip whose archive digest differs"):
     withDiskCache: cache =>
@@ -874,6 +876,11 @@ object ActionCacheTest extends BasicTestSuite:
       keepDirectory = false
     )
 
+  def assertMaterialized(cache: DiskActionCacheStore, p: Path): Unit =
+    if Util.isApfs(cache.casBase) then
+      assert(!Files.isSymbolicLink(p), s"$p was symlinked instead of copied")
+    else assert(Files.isSymbolicLink(p), s"$p was not symlinked into the CAS")
+
   def getCacheConfig(
       cache: ActionCacheStore,
       outputDir: File,