Help Won't install new apps or updates

[codezer0]

As the title screen says... for some bizarre reason my phone is refusing to install new apps or let me update existing apps already installed. All it shows me is an error saying "couldn't install on USB storage or SD card."

So what the hell went wrong here? And how do I fix it?

 

[James_Watson]

Perhaps you should check whether the available space on your phone at first. On the other hand, some permission management app may prevent device from installing new apps.

 

[codezer0]

There is plenty of storage. And I wasn't running anything that is supposed to mess with permissions.

 

[codezer0]

Small update.

Used TWRP to do its factory reset.

Annoying that I had to re-install everything, but at least all that seems to work fine now. I still don't understand why it happened in the first place.