ONEUI5.1 breaking phone. Please help

[laurad2702]

I recently updated to ONE UI 5.1 and have since struggled with the phone shutting itself completely down at random times. There's no overloading of apps, I'm not even pushing the phone (ie. Watching YouTube or netflix, checking emails). Is there any fix? Can I undo the update? I just want to be able to use my S21+ phone, I only bought it in November, and it was new to me. 

[nowdeleted]

What does the phones device care say ?? As I'm confused with all the ui 5.1 reports as I have noticed with my s21 there is no difference. With up to 2 days battery life and the phone is working better.
I don't have Bluetooth enabled as noting is connected WiFi is connected. No vampire apps are enabled and dark mode with extra dim. Adaptive brightness is disabled and it is manually set.

[Bigtasty65]

Have you tried performing a factory reset after the update?

[laurad2702]

I've cleared caches, ran the security scans etc. Nothing flags any issues at all

[laurad2702]

I'd really like to avoid doing that if I can, don't want to lose anything

[laurad2702]

This is the device care page

[nowdeleted]

This is mine and taken off its wireless charger at 5am so 13 hours and still doing good

[Bigtasty65]

Yeah I know what you mean. Anything important such as pictures and maybe even chats. Need to be backed up first. An SSD or memory stick can be relatively cheap to obtain nowadays.
Unfortunately though it may be the only solution to sort this problem out. If you took it to a Samsung store, I'm pretty sure they would reset it with no saving of the data on it.

[JAMES4578]

There tends to be reports of greater battery depletion following updates, however may take just a little time to settle down.  The op  though was talking about shutdowns.  Look at Device Care, are any issues identified and do are putting some apps which are not used a great deal into Sleep Mode? If you using 3rd party apps sometimes they can cause issue and can be pinpointed by starting in Safe Mode.   https://www.samsung.com/uk/support/mobile-devices/how-to-start-my-galaxy-device-in-safe-mode/  

However may not be the case, it is advisable to wipe the cache partition after updates. This deletes temporary files but has no impact on your Data.  Follow these steps:

1. Turn off the device.
2. Connect To Computer or plug in USB-C Headphones , Press and hold the Volume Up key and then press and hold the Power key
3. When the Android logo displays, release all three keys.
4. An 'Installing system update' message will show for 30 - 60 seconds before the Android system recovery menu options appear.
5. Press the Volume down key several times to highlight wipe cache partition.
6. Press Power key to select.
7. Press the Volume down key to highlight yes, them and press the Power key to select.
8. When the wipe cache partition is complete, Reboot system now is highlighted.
9. Press the Power key to restart the device.

Apps can also be repaired from the Same Recovery Menu.    I would try this before a Factory Reset but sometimes this is necessary .  However ensure that you back up your Data before  performing the Factory Reset.

The software cannot be rolled back via official means.

[keith30]

Yeah, don't do a factory reset like some people suggest as that is drastic step to take and unless you've backed up it's risky. Check your device care and see what the auto optimization says as if that is turned on then that would be answer as to why it keeps shutting down and restarting.