App killing was significantly increased on Samsung's Android Pie flavor. Adaptive battery is much more eager than in stock Android.
After 3 days any unused app will not be able to start from background (e.g. alarms will not work anymore). For the proper work user should turn off Adaptive battery and Put apps to sleep options using instructions below.

Important: Even when these options get disabled, Samsung may re-enable them later after a firmware update!

Android 9 (Pie) and newer devices

For Samsung Pie devices you should verify 2 main settings:
- Allow background activitiy and Optimize battery usage

- Allow background activity

To allow application work in the background:

  1. Go to Settings → Apps

  2. Find your application and tap on it

  3. Tap on Battery

  4. Switch on Allow background activity

Steps on Samsung Galaxy S20:

Optimize battery usage

To exclude application from battery optimization:

  1. Navigate to your app’s battery screen (1-3 steps from Allow background activity)

  2. Tap on Optimize battery usage if it says Optimize battery

  3. Find your application in the list and switch off toggle

  4. Navigate back to app’s battery screen and check that Optimize battery usage says Not optimized

Steps on Samsung Galaxy S20:

Pre-Pie Android versions

With the introduction of Galaxy S8 (and with some earlier experiments), Samsung has introduced a flawed attempt at prolonging battery life called App power monitor.

For your apps to work correctly, please whitelist them in App power monitor.

How to do that:

Open the Settings > Device maintenance > Battery and at the bottom you’ll see a list of your most frequently used apps. You can manage apps individually or in a group by selecting them and tapping the big Save power button. Apps that are sleeping will appear in the Sleeping apps list at the bottom (tap it to expand the list). Scrolling further — all the way to the very bottom — and you’ll find Unmonitored apps. These are apps that you specifically want to exclude (whitelist) from App power monitor evil reach.

In the Unmonitored apps menu, you can tap the 3-dot menu to add or delete apps from the list. Rather than bothering with any of that, you can just turn off the App power monitor feature completely as it has little-to-no impact on battery life and only serves to handicap the normal functioning of your Galaxy device.

It’s excessive and in some cases downright misleading, using scare tactics to keep you reliant on Samsung’s software when other Android devices get by just fine without it.


Phone settings > Applications > select three dot menu (top right corner) > Special Access > Optimize Battery usage > Find your app on the list and make sure that it is not selected.

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