I found out the problem. The anti virus software (Bullguard) blocked it. I had bullguard open during launching android studio and a popup asked for permission for adb.exe. I didn’t get this popup when I hadn’t open android studio and bullguard together.

Some time ago, my android studio got a problem. It can’t find my phone. I get this error:

Unable to run 'adb': null

'C:UsersGebruikerAppDataLocalAndroidSdkplatform-toolsadb.exe start-server' failed -- run manually if necessary

When I open the taskmanager I can see adb.exe opened multiple times, but I am unable to force stop it.

I didn’t have this problem before. I tried everything I could find on the internet. I deleted and downloaded android studio multiple times, made sure all the files were gone, tried an older version, tried the no .exe installer but none worked.

I also checked the cable and tried another one.
My computer can see my phone because it’s listed in the explorer so the problem is with android studio.

EDIT: I tried to run on an emulator, but got the same error and another one:

ERROR: AdbHostServer.cpp:102: Unable to connect to adb daemon on port: 5037

EDIT 2: I downloaded android studio on a different computer and had no errors. I used the same device and usb cable. Everything worked normally so the problem is with my computer.

I hope someone can help me.

I thank you in advance!