diff --git a/pkg/compute/models/guest_actions.go b/pkg/compute/models/guest_actions.go
index 5ab4cc8793..cca7a00439 100644
--- a/pkg/compute/models/guest_actions.go
+++ b/pkg/compute/models/guest_actions.go
@@ -1175,7 +1175,10 @@ func (self *SGuest) PerformRebuildRoot(ctx context.Context, userCred mcclient.To
 
 func (self *SGuest) GetTemplateId() string {
 	gdc := self.CategorizeDisks()
-	return gdc.Root.GetTemplateId()
+	if gdc.Root != nil {
+		gdc.Root.GetTemplateId()
+	}
+	return ""
 }
 
 func (self *SGuest) StartRebuildRootTask(ctx context.Context, userCred mcclient.TokenCredential, imageId string, needStop, autoStart bool, passwd string, resetPasswd bool, allDisk bool) error {