Problem:
A user has Excel 2010 and is attempting to open an Excel document from our Office 365 Sharepoint server. Excel Crashes when attempting to open the file with a faulting file "mso.dll"
Modifiers
The same file, when dowloaded and opened locally does not cause Excel to crash. Other Excel files from the sharepoint server continue to force it to crash.
Anyone have any ideas as to what the problem may be?
Update
A different user in my org is reporting the same issue. Updates were installed last night for both of these users. Anticipating that may be the issue. Testing now. Updates installed last night were:
KB3093983 Security Update 10/14/2015 NT AUTHORITY\SYSTEM
KB3097966 Security Update 10/14/2015 NT AUTHORITY\SYSTEM
UPDATE 2
Appears to be related to opening a ".xls" or ".xlsx" file from Sharepoint (office 265) in Excel 2010. Might be related to a "trusted sites" issue.
Update 3 – December 4th
Removing the updates listed above no longer seems to fix the issue. Looks like it is a new update or something that is breaking it again.
Best Answer
We had the same issue, but we are all 2010 - Office and SP. We uninstalled KB3055034 and it solved the issue for us. The update deployed a new mso.dll file. If you check the Event Viewer, you should see this in the application log.
https://support.microsoft.com/en-us/kb/3055034