Hey BerserkIvix,
Go into your Program Files and look for the ‘Epic Games’ folder which contains the ‘Launcher’ folder. Open up this folder and delete any temporary or backup versions of the engine you do not need. You might need to go into the ‘Backup’ folder as well as the ‘VaultCache’ folder to locate the corrupted version. What version of the engine are you attempting to install?
Thank you,