Cmd quits after mbam scan and quarantine

Question

Recently I scanned disk with MalwareBytes Anti-Malware and then accepted quarantine of specific registry key (don't remember which one was that) which seemed to be related to cmd.exe. After this scan and quarantine cmd.exe is starting, changing the window size to very small and quitting in less than a second. Even from powershell it does the same but leaving me in powershell, not closing the powershell window. I was suspecting some malware but nothing is founded by MBAM. There could be an edition of registry key related to cmd which MBAM has deleted and now it is not working properly.

What can I do to fix the problem with cmd.exe?

Answer 1

This was malware named "Sound Mixer", a cryptocurrency miner. Not detected by MalwareBytes Anti-Malware, but detected by MalwareBytes Anti-Rootkit. I've removed the AutoRun key in [HKEY_CURRENT_USER\Software\Microsoft\Command Processor] and now cmd is working fine.