Groupwise 2014 with SP

One of our sites is down to 12GB of space on their groupwise partition, we have no more space it can use, we've gone around setting up archiving on a lot of PC's even though auto archiving was set it doesn't seem to be doing it? Anyway setting up archiving individually on the archives is working on those mailboxes, they are going down but the space on the server isn't.

I know it only holds one copy etc... so that it's not directly proportional.

But, my question is about Reclaiming Unused Disk Space, is it a safe tool to run? I've not run it before so i'm thinking it's time to give it a whirl and see if it works it's magic on the database, but i generally just want to check that it's a safe tool to use, even if it doesn't claim back much space, it's how likely is it to corrupt the database, if it's a very low percentage then i'll happily give that a whirl Friday evening and see what it does.

The database is currently around 500GB