If you have a installed Office 2016 preview version of office 2016/office 365 trial then its probably time for it expire after 180 days of free trail. Once this period expire, Office 365 trail will go to read only mode and won’t allow you to edit any documents.
Luckily like every microsoft product, Office 365 can also be rearmed to extend the trail beyond the official office 365 trail period.
To extend office 2016/office 365 trial period
- On your computer go to C:\Program Files (x86)\Microsoft Office\Office16. For 32 bit installation go to C:\Program Files\Microsoft Office\Office16
- Now run OSPPREARM.EXE as administrator and all done.
The next time you open Office 2016 Application it will ask to activate the new trail period. Just click on next to activate it and you will get your new 30 days extended trail period.