I'm running Fabrication CADmep 2016.  When I try to open a .dwg file it often takes a LONG time or doesn't open at all.  This forces me to End Task that session of autocadd, so I then lose any work on other files that were open in that session.  My only work around has been to open the .dwg on another, unaffected, computer and 'save as' then close.  After that the dwg opens in seconds on my computer.  But after a couple of times of saving and closing the file it becomes slow or wont open on my computer again.  This has been happening for about a year and driving me nuts.  Any ideas????