If you’ve installed Avast in your computer, sometimes, you might have noticed instup.exe running in the Task Manager under the Processes tab, this process with the description Avast Antivirus installer runs from the location C:\Program Files\AVAST Software\Avast\Setup. You can notice it on TM also when you change or repair installed Avast components.
When it is working, it is probably updating virus definitions VPS or program (Avast’s) by decompressing packages it has downloaded, which does require more bandwidth to do that, hence it may be using more system resources, that’s normal. You’ve to worry about it only when it runs constantly for a longer period of time. Normally, it will go away after a few minutes, if it’s not, you need to follow the instructions below to stop it.
Preventing instup.exe of Avast from running constantly in your computer
1. Disable self-defense module, here are the steps for it: Open Avast user interface >Settings >Troubleshooting, uncheck ‘avast self-defense module’.
Note: It’s there to protect Avast files and registry entries from being deleted by malware.
2. And delete ‘Update’ log file in this directory ‘C:\ProgramData\AVAST Software\Persistent Data\Avast\Logs’.
After completing the above step, enable the self-defense module again.
Hope that helps. If you’ve any doubts about this process, feel free to ask me in the comments.