Sometimes, extension can be partially downloaded, for example 90%. We can still install it, because there is no integrity check (that might me another bug). But, we cannot Remove it from Extension Manager. Deleting files from user profile crashes LO, and we get "runtime error" in soffice.bin. What we need is a "Purge extension" or some other way to completely remove it, including any configuration files, configmgr.ini, backenddb.xml, uno_packages.db, etc. For issues like this, you should Add Component "Extensions", like in https://bugs.freedesktop.org/show_bug.cgi?id=33179.
[This is an automated message.] This bug was filed before the changes to Bugzilla on 2011-10-16. Thus it started right out as NEW without ever being explicitly confirmed. The bug is changed to state NEEDINFO for this reason. To move this bug from NEEDINFO back to NEW please check if the bug still persists with the 3.5.0 beta1 or beta2 prereleases. Details on how to test the 3.5.0 beta1 can be found at: http://wiki.documentfoundation.org/QA/BugHunting_Session_3.5.0.-1 more detail on this bulk operation: http://nabble.documentfoundation.org/RFC-Operation-Spamzilla-tp3607474p3607474.html
I decided to close this as WONTFIX because it open for long time, and there are more important issues. It's not so important and we can create a new profile without a damaged extension, although it would require to customize profile again.
*** Bug 143259 has been marked as a duplicate of this bug. ***
*** Bug 143502 has been marked as a duplicate of this bug. ***
New by duplicates.
Here is the erroneous extension that is able to produce: Atttachment 173887
You can still reproduce using attachment 173887 [details].