STFE 9.7.3, Win10x64
Can't get it away, after closing it appears again - must shut Excel down with task manager.
On shutting down apears this:
Initialization [Warning] Assembly SEOTOOLS.XMLSERIALIZERS could not be loaded from resources.
Initialization [Warning] Assembly SEOTOOLS.XMLSERIALIZERS could not be loaded from resources.
Runtime [Error] Unexpected error trying to run SyncMacro for queued macro execution. : NullReferenceException - Object reference not set to an instance of an object.