diff --git a/src/components/structures/MainSplit.js b/src/components/structures/MainSplit.js
index ee6294e0ce..fe9b171c20 100644
--- a/src/components/structures/MainSplit.js
+++ b/src/components/structures/MainSplit.js
@@ -55,8 +55,10 @@ export default class MainSplit extends React.Component {
     }
 
     componentWillUnmount() {
-        this.resizer.detach();
-        this.resizer = null;
+        if (this.resizer) {
+            this.resizer.detach();
+            this.resizer = null;
+        }
     }
 
     componentDidUpdate(prevProps) {