diff --git a/compiler/test/dotty/tools/dotc/printing/PrintingTest.scala b/compiler/test/dotty/tools/dotc/printing/PrintingTest.scala
index ebbc08e49d91..460d8d459718 100644
--- a/compiler/test/dotty/tools/dotc/printing/PrintingTest.scala
+++ b/compiler/test/dotty/tools/dotc/printing/PrintingTest.scala
@@ -21,12 +21,6 @@ class PrintingTest {
   val testsDir = "tests/printing"
   val options = List("-Xprint:typer", "-color:never", "-classpath", TestConfiguration.basicClasspath)
 
-  private def fileContent(filePath: String): List[String] =
-    if (new File(filePath).exists)
-      Source.fromFile(filePath, "UTF-8").getLines().toList
-    else Nil
-
-
   private def compileFile(path: JPath): Boolean = {
     val baseFilePath  = path.toString.stripSuffix(".scala")
     val checkFilePath = baseFilePath + ".check"
@@ -42,8 +36,20 @@ class PrintingTest {
     }
 
     val actualLines = byteStream.toString("UTF-8").split("\\r?\\n")
-
-    FileDiff.checkAndDump(path.toString, actualLines.toIndexedSeq, checkFilePath)
+    // 'options' includes option '-Xprint:typer' so the first output line
+    // looks similar to "result of tests/printing/i620.scala after typer:";
+    // check files use slashes as file separators (Unix) but running tests
+    // on Windows produces backslashes.
+    // NB. option '-Xprint:<..>' can specify several phases.
+    val filteredLines =
+      if (config.Properties.isWin)
+        actualLines.map(line =>
+          if (line.startsWith("result of")) line.replaceAll("\\\\", "/") else line
+        )
+      else
+        actualLines
+
+    FileDiff.checkAndDump(path.toString, filteredLines.toIndexedSeq, checkFilePath)
   }
 
   @Test
diff --git a/compiler/test/dotty/tools/vulpix/FileDiff.scala b/compiler/test/dotty/tools/vulpix/FileDiff.scala
index 2ff3524ce772..7eef57d4888b 100644
--- a/compiler/test/dotty/tools/vulpix/FileDiff.scala
+++ b/compiler/test/dotty/tools/vulpix/FileDiff.scala
@@ -3,6 +3,7 @@ package dotty.tools.vulpix
 import scala.io.Source
 import java.io.File
 import java.lang.System.{lineSeparator => EOL}
+import java.nio.file.{Files, Paths}
 
 object FileDiff {
   def diffMessage(expectFile: String, actualFile: String): String =
@@ -34,15 +35,19 @@ object FileDiff {
     outFile.writeAll(content.mkString("", EOL, EOL))
   }
 
-  def checkAndDump(sourceTitle: String, actualLines: Seq[String], checkFilePath: String): Boolean =
+  def checkAndDump(sourceTitle: String, actualLines: Seq[String], checkFilePath: String): Boolean = {
+    val outFilePath = checkFilePath + ".out"
     FileDiff.check(sourceTitle, actualLines, checkFilePath) match {
       case Some(msg) =>
-        val outFilePath = checkFilePath + ".out"
         FileDiff.dump(outFilePath, actualLines)
         println(msg)
         println(FileDiff.diffMessage(checkFilePath, outFilePath))
         false
       case _ =>
+        val jOutFilePath = Paths.get(outFilePath)
+        Files.deleteIfExists(jOutFilePath)
         true
     }
+  }
+
 }