diff --git a/src/main.ts b/src/main.ts
index d94c982..c83e4d0 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -12,7 +12,7 @@ async function run(): Promise<void> {
 
     core.setOutput('time', new Date().toTimeString())
   } catch (error) {
-    core.setFailed(error.message)
+    if (err instanceof Error) core.setFailed(error.message)
   }
 }