This is serious stuff and still happens in Slicer-4.4.

Users already reported Slicer not working and it took a lot of time to figure out what's happening and then explain them to go to their AppData dir, find the ini file corresponding to the corrupted Slicer release, delete it (this deletes all other non-default settings, too).

Not just for SlicerRT but for other extensions, too (for example VolumeClip). Maybe impacts all extensions, or all that contains Python scripted modules?

Does this process to uninstall the application work to reset things?

http://www.slicer.org/slicerWiki/index.php/Documentation/4.4/FAQ#How_to_uninstall_Slicer.3F

Uninstall does not help. The corrupted Slicer version becomes permanently broken on a computer where any extensions are uninstalled.

The reason is that c:\Users\<yourusername>\AppData\Roaming\NA-MIC\Slicer-NNNNN.ini becomes corrupted and it is not touched by the installation/uninstallation process.

On the most recent nightly build not just the Python modules not appear but Slicer sometimes will not even start if previously an extension was uninstalled.

What happens if you uninstall it manually? Maybe we should add this step to the uninstall target. Or maybe we offer a script that performs the cleanup? (Or, better, of course, we fix the actual bug!).

I'm not sure what you mean by manual uninstall. If you run Uninstall from the start menu then the ini files are extensions are not touched. If we add the ini file to the uninstall target then we should delete all the extension files too (the extension files would be orphaned without the corresponding ini file).

This is a serious issue and it is present since almost 3 months already in both the latest stable version and all nightly versions.

We already know about a lot of occurrences and surely there are many more people who just give up using or trying Slicer because of this problem.

Is somebody working on the fix?

I think we are saying the same thing - it sounds like extension installation should add some extra hooks to the uninstaller so that everything gets properly cleaned up.

Yes, removing extensions and config files on Slicer uninstall could be nice, but not essential (some people might actually prefer to keep settings).

The main issue though is that the ini files get corrupted when uninstalling extensions (not Slicer).

What is the plan for the fix? I may try to investigate this but the best would be if Jc or others who implemented extension installation/uninstallation could work on it.

Jc is travelling to SLC today so we may be able to discuss it in the coming days. I personally have not looked at all at any of this.

Fixed in rev 24140

Thanks Andras.