sage hr uploading t4 from sage 50 canada

Trying to upload my employees t4's to sage HR.  Has crashed 4 times I've tried doing all employees.  Then I tried just doing those with last name starting with A and it worked.  Tried to upload the B's which there is more of and it crashed again.  Please tell me I don't have to do them 20 at a time.  It would be just quicker to print and mail if that's the case!!!