No device appears for Androidstudio’s "run"

Question

Everything was normal until I went to mount an emulator with api 21, during the process there was disk error without space, my Androidstudio was in a hard drive partition with little space, after the error or it started an Indexing process, and stayed there for almost half an hour until I decided to close it and open it again, then when I click on "run" neither emulators appear nor my mobile connected.

I’ve already tried:

• Testing with two different cell phones.
• Build a new emular image with another android version.
• Start the emulator by AVD Manager, it starts the ones already created but when I click on "run" nothing appears.
• I’ve reinstalled Androidstudio.
• I already installed it somewhere else and started the new and even then nothing appears and there is no error.

He just gets like this:

Answer 1

The problem was in the process of adb.exe that was listened but doing nothing, to solve it was simple, just open the task management and finish the process, then go back to Android Studio and try to run again.

Answer 2

You can try going back to android studio the initial settings.

Go to user folder

C:\Users\Seu_usuario

On this page, you should have a folder named after .AndroidStudio with its version assigned to the folder name.

Make a backup of this folder, and then delete it, that remove your settings.

If you have tried this before, try reinstalling the api. Go on Default Settings

Under SDK Platforms, install the versions, reinstall the Apis, and try new ones. Then go on SDK Tools, go in Show Package Details and make sure to mark the Android SDK Build-Tools in the versions you chose before.