[Help] Where does outlook store .pst files for additional mailboxes

Hey spiceheads,
This is probably quite straight forward but I just can't seem to find the answer anywhere online.
I've added an additional mailbox to my outlook, it's fully updated but I just cant find the .pst file for it. If I right click on the mailbox and click open file location It says "attempted operation failed, object cannot be found". I've check the usual places, "appdata/local/microsoft/outlook" along with my user area but I'm coming up short.

Any help would be much appreciated, kind regards -Nathan