Agree that when you turn on a smartphone or tablet based on Android systems, after the main OS modules are loaded, as evidenced by the system startup message, an additional notification appears about the start of optimization of installed applets, many mobile phone owners technology, this causes some misunderstanding. It is especially worth considering that such optimization may apply not to one or two applets, but to several dozen, and in time it can take up to thirty minutes or more. How to disable application optimization when you turn on "Android", then we'll figure it out. But first, let's find out for what reason this incomprehensible process starts for no reason.
When you turn on Android, the system writes: "Application optimization": what is the reason?
In general, strictly speaking, optimization is a completely safe system process, which is designed to arrange the installed applets in order to use them after loading the system components. Usually, the appearance of such optimization can be observed either when the smartphone or tablet is turned on for the first time immediately after purchase, or after a complete reset to the factory settings, which could be performed on a running system or special tools were used for this, located in the boot menu, or when updating the system, or after flashing.
Also very often such situations can be observed when combining SD memory cards with internal storage, when some applications are automatically installed on it. But each time the device is turned on, such processes should not start. If this happens all the time, it's time to think about how to turn off application optimization when you turn on Android.
It is believed that the main reasons for such absurd behavior of the system are either an excessive number of applets that start together with system components, or an overflow of the system cache or the installed applications themselves, or, more simply, cluttering up the OS with temporary files like this happens quite often on the same Windows systems. Thus, you need to either disable the autorun of unnecessary programs, or clear the cache.
How to fix application optimization when turning on Android: deactivating third-party applets
Alas, Android systems have their own means of deactivationthere is no autorun of unused applets, or they are hidden from the user's eyes so deeply that no root rights help. However, if we talk about how to disable application optimization when Android is turned on, and at the same time remove unnecessary applets from the system startup section, you can do it much easier.
If you have root permissions, All-in-One Toolbox is a good choice.

If you don't have root rights, which can be obtained far from all known mobile devices, you can use two applets in conjunction - Droid Optimizer and Doze.

The first one has the ability to manage autorun (App Manager section), including the deactivation of most system services, and the second one can completely block the operation of unnecessary applications after the system has loaded by a kind of “freezing” them.
Cache cleaning by means of the system and special programs
But you should not rely on such methods only, although you can also clean cached data in optimizer applications.

In particular, the same Droid Optimizer may offer to apply the one-touch cleanup function or use a special section where the user can choose to clear the cache and temporary files by running it as a separate process.
If there are no such applications at hand, you can use the built-insystem tools, however, it will take much more time for all the operations performed. Just go to the settings, go to the applications section, tap on the name of the desired applet, stop it and click the clear cache button. For a long time? Yes, of course!
Cache wipe
Thus, let's simplify our task and see how to turn off application optimization when you turn on Android, so to speak, in one fell swoop. You can perform such an operation from the start menu of the Recovery mode. To enter, when you turn on the device, you must hold the power button and the volume down key. Most devices use this combination /, but sometimes the volume up button or even other combinations can be used (they can be found in the technical description of the device, for example, on the manufacturer's website, since such data is usually not indicated in the user manual).

After entering the menu, using the volume buttons, check the Wipe cache partition item, which will activate the complete cleaning of the cache memory, after which the device will only need to be rebooted by selecting the Reboot system now item for this.
Note: if this partition supports clearing the Dalvik cache, it's a good idea to do that as well. Please note that none of the described operations will lead to the removal of installed applets or your personal data and files. So you can be absolutely calm about this.