diff --git a/src/main/java/com/google/devtools/build/lib/remote/RemoteExternalOverlayFileSystem.java b/src/main/java/com/google/devtools/build/lib/remote/RemoteExternalOverlayFileSystem.java
index 89c7b61f75b256..3425f500a697e6 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/RemoteExternalOverlayFileSystem.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/RemoteExternalOverlayFileSystem.java
@@ -145,6 +145,11 @@ public void beforeCommand(
   }
 
   public void afterCommand() {
+    if (cache == null) {
+      // Not all commands cause beforeCommand to be called, but afterCommand is called
+      // unconditionally.
+      return;
+    }
     this.cache = null;
     this.inputPrefetcher = null;
     this.reporter = null;