Outlook for Mac - Crash on PST import

I have several different PST files (mostly the same data, just different saves from different dates, most below 1gb), but they all cause my Outlook for Mac to crash.  They import for a while and I can see old folders uploading and the blue progress bar filling up , but 2/3 to 3/4 of the way to completion, outlook crashes and when I reopen nothing got imported.

Somebody please help!

Thanks