diff --git a/src/flux/stores/workspace-store.coffee b/src/flux/stores/workspace-store.coffee
index f92e95f102..9f3f77a309 100644
--- a/src/flux/stores/workspace-store.coffee
+++ b/src/flux/stores/workspace-store.coffee
@@ -45,7 +45,8 @@ class WorkspaceStore extends NylasStore
       @trigger()
 
     NylasEnv.config.observe 'core.workspace.interfaceZoom', (zoom) =>
-      require('electron').webFrame.setZoomFactor(zoom)
+      if zoom and _.isNumber(zoom)
+        require('electron').webFrame.setZoomFactor(zoom)
 
     NylasEnv.commands.add 'body', @_navigationCommands()