STOP
You do not always need to 'wipe', or 'format data', etc. etc.
These sometimes can cause more problems than there were before.
If you can get into TWRP, either by booting or through Fastboot,
try it!
TWRP is VERY FRIENDLY
If you are having problems, and have no data (or even lost your data and have no chance of getting it back), but still want to try and keep your precious files, there is a very simple solution!
Taken from
FAQs on the official TWRP website:
"If you are switching ROMs (changing from one ROM to a completely different one) then you should perform a factory reset. A factory reset wipes data and cache (which includes dalvik cache). A factory reset will also wipe sd-ext and android_secure if your device has those items. 99% of the time, this is all that you need to wipe and you only need to do it once, not three times as some people would lead you to believe.
....
"The vast majority of ROMs wipe system as part of the zip install. This means that in most cases you do not need to wipe system... ever.
....
"If you're installing a nightly update, then oftentimes you don't need to wipe anything at all. However, if you encounter strange behavior, then you may want to consider performing a factory reset.
....
"Depending on your device and its configuration, you may have options for wiping internal storage, external storage, sd-ext, android_secure, and/or an option for formatting data. There's almost no reason that you would ever need to use these items."
I always advocate doing backups; TWRP's backups are one of the best. It backs up all of the apps, their data, widgets, and restores everything (icons!) in the same location. I use it all the time.
Yesterday, I tried a
Factory reset (never done one before, ever!) I backed
everything up and copied it to my PC. I went back into TWRP and did a factor reset from within TWRP. And rebooted.
It was like a brand new phone - going through the complete setup proccess, from scratch. However, all of my files
were still there!!!!
So, I went back into TWRP, and just did the restore, and I was back to where I was - having lost nothing.
A
Factory reset is really quite painless, but can cover several things - correctly.