I have office 365. Recently loaded Windows 10. Now, when I open a One drive excel file, properties tells me it opens with Microsoft Open XML converter. I am unable to save files, what is happening?

• Moved by Kate LiMicrosoft contingent staff Thursday, August 20, 2015 9:13 AM

Hi ikendall,

>>Recently loaded Windows 10. <<, as far as I know users got different problems about Office after upgrading to Windows 10.

I suggest you try to repair Office and check if it works fine. About how to repair Office in Windows 10, please refer to this article:
https://support.office.com/en-NZ/Article/Repair-an-Office-application-7821d4b6-7c1d-4205-aa0e-a6b40c5bb88b

Hope it's helpful.

Regards,

Emi Zhang
TechNet Community Su