it was working fine before the windows 8.1 upgrade last night. now my analysis addin crashes excel everytime i run it. i've deleted office 365 and reinstalled, repaired it twice. 

nothing works. 

Hi Appraiser,

So this happens right after installing Windows 8.1 updates. Have you ever checked what kind of updates have been installed?

You've mentioned "I've deleted Office 365", I'm assuming you have Click-To-Run version of Office installed, correct? Is your Office installation up to date?

I would suggest we first have a look at the event logs and see if it says anything useful there.

If you would like us to help analyze the logs, you can send the log file to this email account: ibsofc@microsoft.com (please use the link of this thread as the subject).

Regards,

Ethan Hua
TechNet Community Support