diff --git a/.github/workflows/actions.yml b/.github/workflows/actions.yml
index 2cfb4e97238..b25a9cc9feb 100644
--- a/.github/workflows/actions.yml
+++ b/.github/workflows/actions.yml
@@ -109,7 +109,6 @@ jobs:
           - cmd /C %GITHUB_WORKSPACE%\ci\mill.bat -i -d -k "integration.thirdparty.{local,forked}"
           - cmd /C %GITHUB_WORKSPACE%\ci\mill.bat -i -d -k "contrib.__.test"
 
-
     runs-on: windows-latest
 
     steps:
diff --git a/main/src/mill/main/MillServerMain.scala b/main/src/mill/main/MillServerMain.scala
index 0f4cca57bae..f344d1c42eb 100644
--- a/main/src/mill/main/MillServerMain.scala
+++ b/main/src/mill/main/MillServerMain.scala
@@ -208,6 +208,8 @@ class Server[T](
     Thread.sleep(5)
     try t.stop()
     catch {
+      case e: UnsupportedOperationException =>
+      // nothing we can do about, removed in Java 20
       case e: java.lang.Error if e.getMessage.contains("Cleaner terminated abnormally") =>
       // ignore this error and do nothing; seems benign
     }