Changed over from McAfee to NORTON Security as requested - tablet came up with a DECRYPTION UNSUCCESSFUL message and when I put in password it said Data Corrupt and only could only RESET to factory settings which lost me everything on the tablet - this happens every time I turn on my tablet - sort of Ground Hog Day - advice on Google indicates this is a problem far too serious for someone not into IT - tablet now useless!!!!
Have you tried clearing the cache first before doing the factory reset, it's not difficult but the exact procedure can vary a little from make to make.
You need to access the Android Recovery menu to do so, this is where the procedure can differ from make to make but generally it follows the same process.
Thanks - have been through the 'solution' many times - reloaded Internet, etc, and working OK - turn off to test - on restart it asks for my 'old' Password (4 numbers) even though I declined this security feature when reloading and when I put in Password the next message is DECRYPTION UNSUCCESSFUL, Data Corrupt and you have to RESET TO FACTORY SETTINGS - Ground Hog Day!! Will try to remove need for the PASSWORD?
What Android version are you running?
I know from my own experience that the passkey is resilient to factory reset in Android 10 (I was asked to enter the last passkey on restart), perhaps it is also resilient in Android 8, I couldn't say. Try removing any security measures and restarting the tablet before trying to reset it again
When I reset my Android 10 tablet, I was surprised to find it asking for my previous pin number upon restart, I expected that to have been forgotten as part of the reset but clearly it wasn't.
I entered my old pin number (as requested) and continued with the set process as normal which was all that was necessary and I could have left it at that but curiosity got the better of me so I went back into Settings/Security/Screen Lock and removed the pin number, restarted the tablet and then did another factory reset and everything was fine after that
I wish I could help but that's me stumped I'm afraid. The only way I can see any of that maybe happening (excluding a fault condition) is if the PIN number has been cached and not cleared which brings us back to my post at message 2