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Question S21 Ultra started to lag and stutter since yesterday out of NOWHERE!! tried everything but still there?

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karandevilocs

Senior Member
Dec 6, 2010
292
44
hey so my s21 ultra which was working normal until yesterday started to lag out of nowhere ... the only thing that i did different in these 2days was gaming with my new clip on xbox controller and testing different games ,

I didn't install anything new EXCEPT that octopus key mapper and then Mantis gamepad pro but i didn't really set them up EXCEPT i just tried connecting my s21 ultra to my note 8 via usb c just to test if it worked but then note 8 ran out of battery like crazy...

It just looks like that app did it but i uninstalled all of them but still it is there...

any help? i don't want to reset anything !
 

blackhawk

Senior Member
Jun 23, 2020
5,810
1,766
Clear system cache.
Try in safe mode.
See which system apps are the most active, delete their data.
A user hidden setting may have been altered by a poorly written app, a possible rootkit etc or a hardware failure.
Factory reset if you can't find it soon.
 
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blackhawk

Senior Member
Jun 23, 2020
5,810
1,766
That last line will make things difficult.

That would be the most foolproof software solution for a non rooted phone IMO. If you reconsider, I'd suggest a full hard reset.
Hard reboot or factory reset?
A hard reboot is fine. However a hardware issue may be present if this is needed.

Factory reset; it's always preferable to find and correct the root cause rather than doing a factory reset as the issue is likely to reoccur.
Exceptions; unremovable malware, rootkits, major firmware updates, old loads and altered hidden user settings.
 
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blackhawk

Senior Member
Jun 23, 2020
5,810
1,766
I have the same problem, some video on gallery or YouTube, system crash, dji mini 2 app...no display, some apps crashes, android auto heating up the phone....
Backup all critical data now.
Find the cause before it boot loops you.
These are typically the only warnings, if any, before a boot loop. This is not normal behavior.

See which apps are using the most battery, try force stopping them, clear their data, disable them temporarily if possible.
Disable any power management!!!
If using a 3rd party launcher or power management, disable it!!!

Try in safe mode.
Take all factory installed apks especially system apks back to their factory load versions.
Turn off all cloud apps including Google backup Transport for now. Turn off Google Firebase.
Turn off all Google, Samsung, and carrier feedback.
Try temporarily disabling Google play Services, clear it's data.
Reset network settings.
Clear system cache.
Try a hard reboot.
 

karandevilocs

Senior Member
Dec 6, 2010
292
44
does it lag in safe mode?

That last line will make things difficult.

I have the same problem

Backup all critical data now.
so i fixed it after going to safe mode and realizing that it was not the system apps, then i reinstalled that mantis app and uninstall it again to make sure if it was stuck or not also there was this app called : NET SPEED INDICATOR that was updated recently and was flagged as crashed in device monitor so i uninstalled it too and boom, the device was normal again.

so happy that it was a software issue rather than hardware or malware one since i keep close control of what i install and not and monitor everything it was surprising to see such things in my phone, after years of Samsung phone usage it was really shocking to see such behaviors on my s21 ultra with freezing and crashing non stop.

thanks for the help guys!
 
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    Clear system cache.
    Try in safe mode.
    See which system apps are the most active, delete their data.
    A user hidden setting may have been altered by a poorly written app, a possible rootkit etc or a hardware failure.
    Factory reset if you can't find it soon.
    1
    does it lag in safe mode?
    submit an error report on samsung members app > + button > error report if you think it's a software issue
    1
    That last line will make things difficult.

    That would be the most foolproof software solution for a non rooted phone IMO. If you reconsider, I'd suggest a full hard reset.
    Hard reboot or factory reset?
    A hard reboot is fine. However a hardware issue may be present if this is needed.

    Factory reset; it's always preferable to find and correct the root cause rather than doing a factory reset as the issue is likely to reoccur.
    Exceptions; unremovable malware, rootkits, major firmware updates, old loads and altered hidden user settings.
    1
    does it lag in safe mode?

    That last line will make things difficult.

    I have the same problem

    Backup all critical data now.
    so i fixed it after going to safe mode and realizing that it was not the system apps, then i reinstalled that mantis app and uninstall it again to make sure if it was stuck or not also there was this app called : NET SPEED INDICATOR that was updated recently and was flagged as crashed in device monitor so i uninstalled it too and boom, the device was normal again.

    so happy that it was a software issue rather than hardware or malware one since i keep close control of what i install and not and monitor everything it was surprising to see such things in my phone, after years of Samsung phone usage it was really shocking to see such behaviors on my s21 ultra with freezing and crashing non stop.

    thanks for the help guys!