diff --git a/io/src/main/scala/sbt/internal/io/Milli.scala b/io/src/main/scala/sbt/internal/io/Milli.scala
index 4d8f1dc4..fe2e4750 100644
--- a/io/src/main/scala/sbt/internal/io/Milli.scala
+++ b/io/src/main/scala/sbt/internal/io/Milli.scala
@@ -12,6 +12,7 @@ package sbt.internal.io
 
 import java.io.{ File, FileNotFoundException, IOException }
 import java.nio.{ ByteBuffer, ByteOrder }
+import java.nio.file.Files
 import java.util.Date
 
 import com.sun.jna.platform.win32.Kernel32
@@ -396,7 +397,7 @@ object Milli {
     if (jdkTimestamps)
       None
     else {
-      val file = File.createTempFile("sbt.io.Milli", "test-file", projectDir)
+      val file = Files.createTempFile(projectDir.toPath(), "sbt.io.Milli", "test-file").toFile
       try {
         val originalTime = getModifiedTime(file)
         setModifiedTime(file, originalTime - 27)
diff --git a/io/src/main/scala/sbt/io/IO.scala b/io/src/main/scala/sbt/io/IO.scala
index 69b9d40b..edb8ca46 100644
--- a/io/src/main/scala/sbt/io/IO.scala
+++ b/io/src/main/scala/sbt/io/IO.scala
@@ -526,11 +526,11 @@ object IO {
   def withTemporaryFile[T](prefix: String, postfix: String, keepFile: Boolean)(
       action: File => T
   ): T = {
-    val file = File.createTempFile(prefix, postfix)
+    val file = Files.createTempFile(prefix, postfix)
     try {
-      action(file)
+      action(file.toFile())
     } finally {
-      if (!keepFile) file.delete(); ()
+      if (!keepFile) file.toFile().delete(); ()
     }
   }