diff --git a/src/main/java/com/google/devtools/build/lib/vfs/RootedPath.java b/src/main/java/com/google/devtools/build/lib/vfs/RootedPath.java
index c74062eacc0869..96e2b0b541d7a7 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/RootedPath.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/RootedPath.java
@@ -16,6 +16,7 @@
 import static com.google.common.base.Preconditions.checkArgument;
 
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
+import com.google.devtools.build.lib.util.OS;
 import com.google.devtools.build.skyframe.SkyKey;
 import java.util.Comparator;
 import javax.annotation.Nullable;
@@ -53,6 +54,11 @@ public final class RootedPath implements Comparable<RootedPath>, FileStateKey {
   @AutoCodec.Instantiator
   @AutoCodec.VisibleForSerialization
   static RootedPath createInternal(Root root, PathFragment rootRelativePath) {
+    if (OS.getCurrent() == OS.WINDOWS && root.isAbsolute() && rootRelativePath.toString()
+        .equals("/")) {
+      throw new IllegalStateException(
+          "Path " + rootRelativePath + ", " + rootRelativePath.getClass());
+    }
     checkArgument(
         rootRelativePath.isAbsolute() == root.isAbsolute(),
         "rootRelativePath: %s root: %s",