diff --git a/common/junit-platform-native/src/main/java/org/graalvm/junit/platform/NativeImageJUnitLauncher.java b/common/junit-platform-native/src/main/java/org/graalvm/junit/platform/NativeImageJUnitLauncher.java
index 8bbde8b9..65d99188 100644
--- a/common/junit-platform-native/src/main/java/org/graalvm/junit/platform/NativeImageJUnitLauncher.java
+++ b/common/junit-platform-native/src/main/java/org/graalvm/junit/platform/NativeImageJUnitLauncher.java
@@ -55,6 +55,7 @@
 import org.junit.platform.launcher.listeners.UniqueIdTrackingListener;
 import org.junit.platform.reporting.legacy.xml.LegacyXmlReportGeneratingListener;
 
+import java.io.File;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.UncheckedIOException;
@@ -218,7 +219,7 @@ private static Path getTestIDsFromDefaultLocations() {
     }
 
     private static Path getGradleTestIdsDefaultLocation() {
-        return Path.of(getBuildDirectory("/build/"))
+        return Path.of(getBuildDirectory(File.pathSeparator + "build" + File.pathSeparator))
                 .resolve("test-results")
                 .resolve("test")
                 .resolve("testlist")
@@ -226,7 +227,7 @@ private static Path getGradleTestIdsDefaultLocation() {
     }
 
     private static Path getMavenTestIDsDefaultLocation() {
-        return Path.of(getBuildDirectory("/target/"))
+        return Path.of(getBuildDirectory(File.pathSeparator + "target" + File.pathSeparator))
                 .resolve("test-ids")
                 .toAbsolutePath();
     }