Is it safe to factory reset my rooted HTC One M8? I rooted my android marshmallow M8 some time ago and didn't flash any custom ROM. Just used SuperSU and Xposed for some modules and that's basically it. Today the phone was forced shut-down at 13% battery (it had that problem for a while) and when I charged it and tried to turn it on, a message pops out saying that there's an internal problem and it may be unstable until I factory reset the phone. And there is indeed a problem. Messages keep popping out saying that google apps are crashing and I basically can't use it.

So, can I just factory reset it like that? Since it's rooted and everything.
Preform backup just in case. Yes factory reset will return it to factory status. If you have custom recovery then just wipe data and cache's. If you have SuperSu system mode do a full factory wipe.