Run-time error '-2147417843 (8001010d)': An outgoing call cannot be made since the application is dispatching an input-synchronous call

This error may occur when switching between windows and applications while using Design Manager. 

To fix this problem the Design Manager Assistant must be disabled.

How to Fix: Disable Design Manager Assistant

1. Click “Help” on the Design Manager toolbar.

2. Uncheck “Show Assistant”.

3. Exit Design Manager and log back in.