Have been using draftsight 2018 Sp3 successfully the past while. This week i have a drawing that is only 1,500kb in size and has 15 or so sheet tabs.  I've had this file crash 4 today , two total crashes and two that locked me out of saving,  but let me save as another file name, but didn't change the file name on the drawing tab.  Located the file on my drive and try open, only to be told another user already has that file open. 

Only ideas I have is that I have 8gb of ram,  18m old HP workstation , but never see more that 4gb of ram used