diff --git a/packages/apollo-client/src/ApolloClient.ts b/packages/apollo-client/src/ApolloClient.ts
index 6c5bac03e08..b729fcc4319 100644
--- a/packages/apollo-client/src/ApolloClient.ts
+++ b/packages/apollo-client/src/ApolloClient.ts
@@ -171,6 +171,7 @@ export default class ApolloClient<TCacheShape> implements DataProxy {
           // Only for Chrome
           if (
             window.navigator &&
+            window.navigator.userAgent &&
             window.navigator.userAgent.indexOf('Chrome') > -1
           ) {
             // tslint:disable-next-line