You cannot disable an extension for a project after you enable it. We recommend you enable only the extensions you need.

https://admhelp.microfocus.com/alm/en/17.0-17.0.1/online_help/Content/WebAdmin/manage_projects.htm?Highlight=%22project%20extension%22 

Hi gbin, 

Thank you for your answer. I agree, you should only activate the extensions you need. The project has been in operation for more than 10 years now and requirements change over time. When migrating from version 17.0.1 to 24.0.1 P1, errors occur and the projects can no longer access the Lab Project, so I wanted to turn off the extension that is no longer used because it has not been used for several ALM versions. So far, there have never been any problems with migrations, which is why the extension was always migrated instead of properly maintaining the project in accordance with the requirements. For this reason, your answer, for which I am very happy, unfortunately does not help me any further. I need a way to disable Lab Extension. 

Kind regards, 

Stefan

I have the exact same situation... someone a decade ago installed an extension in our QC system a demo/eval without ever knowing it would haunt us for years to come.  It was never used and thus has technically added any need data to our world.  But, because Mercury|HP|MF and OpenText say it cannot be removed & we have to "deal with it" over and over during upgrades (with Oracle DB)!  It's a pain and seems to me some smart person would be able to write an uninstall tool or cleanup during an upgrade process / create new tables without the extension artifacts or the like!  If the extension knows where to write .. seems like it could expose where to remove itself and warn of any data loss for the end user to "Accept" or not.

I was going to try it one day but, my time is very limited for developing and testing other products.
If OpenText would take a look ...it might not be that big of an effort and it is sure to make everyone's life easier!

Let me know if you ever find a solution!