Unable to set slug to value used previously I have an entry whose slug I would like to set to 'archive', but when I save it, it is 'archive-1'. There is no existing entry with slug of 'archive' (craft.entries.slug('archive') returns null). There have been previous entries with that slug.
There probably is still an (maybe corrupted) entry in the db with that slug. Have a look at the entries-content table, sort it by slug and you possibly see an entry responsible for your problem.