Microsoft apps won't open

[Bundalings]

Hello friends, I have a Lumia 920 on ATT with WP 8.1 Preview installed, and over the last couple days the Microsoft apps on my phone have simply ceased to function. It?s driving me nuts. I?ve never had any problems with WP before now, but my phone is becoming unusable.

I have not noticed any apps not published by Microsoft not working.

Here are the apps I?ve noticed will no longer open at all (when I tap on the icon it does nothing, when I ask Cortana to open them she loads endlessly):
Calendar
Bing Weather
Bing Food+Drink
Bing Health
Bing News
Reading List
Battery Saver
Podcasts
Video
Games
Folders
Skype (just a blue box on the tile, no icon, and I can?t uninstall it)

These are the ones that still work fine:
Cortana
Messaging
Phone
People
IE
Mail
Store
Office
OneDrive
OneNote
OfficeLens

Music opens but is an endless black loading screen. I can play music through Cortana, however, so it?s still working in the background.

Photos opens but doesn?t load anything from the cloud anymore.

I?ve tried soft resets, making more space on the phone, unpinning and pinning again? I have no idea what to do. Has anyone else encountered this? Any idea for a fix?

I suppose I can go back to WP 8 or factory reset but I?d really rather not.

 

[anon(7900571)]

It looks like a software issue. Why not try a hard reset or try to downgrade to windows phone 8.0 via nokia recovery tool. Backup all your important data before doing this.

 

[Bundalings]

Thanks for the advice. I was hoping there was some easier fix, but a factory reset worked and lets me do some house cleaning so it's not all bad.