diff --git a/src/util/virhook.c b/src/util/virhook.c
index 25d0783bfb5e16883c0c225b07b5684b3fe03d17..ee19382c4a6e655427f3a9f6898fd88e8ac42966 100644
--- a/src/util/virhook.c
+++ b/src/util/virhook.c
@@ -300,7 +300,8 @@ virHookCall(int driver,
     if (ret < 0) {
         /* Convert INTERNAL_ERROR into known error.  */
         virErrorPtr err = virGetLastError();
-        virReportError(VIR_ERR_HOOK_SCRIPT_FAILED, "%s", err->message);
+        virReportError(VIR_ERR_HOOK_SCRIPT_FAILED, "%s",
+                       err ? err->message : _("unknown error"));
     }
 
     virCommandFree(cmd);