I recommend engaging tech support but purging in general can be a
challenge. Crappy interface, long runtimes and frequent errors. The
structured nature of the data can make some purges impossible. I would
recommend doing purges in smaller sets. Similar objects and use folders
to collect items for purging (Just remember where to put them when you
are done). In general, you should purge WTParts, then CAD Drawings, then
assemblies then cad parts.