It’s hard to even hazard a guess based on the lack of information. My whole Avast Folder C:\Program Files\AVAST Software\Avast is only 1.44 GB.
You don’t give the file name or its location ?
You could set everything to default values AvastUI > Settings > General > Troubleshooting > Reset to default.
This however isn’t without risk as any settings you had changed would be lost