I noticed my Galaxy S21's battery started draining super fast right after the recent software update last week. The odd part is that it happens even when I switch to airplane mode and close all apps. I usually get a full day's use, but now it's down to 50% by early afternoon with barely any use. I've already tried clearing the cache partition and rebooting a couple of times, but no luck. Also, I checked battery usage stats and it doesn't point to any particular app hogging power.

Has anyone else experienced this kind of battery drain after an update? What are some less obvious fixes I could try before resorting to a factory reset? Is it possible the update has a bug that might get patched soon?

On 01/22/2026 at 2:45 AM, MellowCat106 said:

I noticed my Galaxy S21's battery started draining super fast right after the recent software update last week. The odd part is that it happens even when I switch to airplane mode and close all apps. I usually get a full day's use, but now it's down to 50% by early afternoon with barely any use. I've already tried clearing the cache partition and rebooting a couple of times, but no luck. Also, I checked battery usage stats and it doesn't point to any particular app hogging power.

Has anyone else experienced this kind of battery drain after an update? What are some less obvious fixes I could try before resorting to a factory reset? Is it possible the update has a bug that might get patched soon?

Sounds frustrating, especially since you’ve already tried the usual tricks like clearing cache and rebooting. Sometimes after a major update, the system can be doing background tasks like re-indexing files or optimizing apps, which can cause temporary battery drain. If it’s been more than a few days, you might want to check if there’s a new patch or update available that addresses battery issues - Samsung often rolls out quick fixes.

Also, have you tried booting into safe mode to see if the drain persists? That can help rule out any rogue apps running in the background despite airplane mode. If safe mode shows better battery life, then it might be a third-party app causing the problem. Otherwise, a factory reset might be the last resort, but hopefully, you won’t have to go that far.