Daz Studio Crashes on Start

Help! I can't start daz studio 4.9. I get a non-specific error everytime. A problem caused the program to stop working. This seems to be the problem area in the log. Help!
2017-05-18 18:59:51.172 Error writing author data!2017-05-18 18:59:51.185 Iray INFO - module:category(API:DATABASE): 0.0 API db info : Loaded "C:\Program Files\DAZ 3D\DAZStudio4\DAZStudio.exe"2017-05-18 18:59:51.185 Iray INFO - module:category(API:MISC): 0.0 API misc info : Iray 2016.3, build 278300.4305, 30 Nov 2016, nt-x86-64-vc112017-05-18 18:59:51.187 WARNING: dzneuraymgr.cpp(403): Could not add path: "C:/Users/paris/AppData/Roaming/DAZ 3D/Studio4/shaders/iray". Due to unkown error -22017-05-18 18:59:51.187 WARNING: dzneuraymgr.cpp(403): Could not add path: "C:/Users/paris/AppData/Roaming/DAZ 3D/Studio4/temp/shaders/iray". Due to unkown error -22017-05-18 18:59:51.201 Iray INFO - module:category(GPU:RENDER): 0.0 GPU rend info : Found 1 GPU with vendor's API.
Comments
Is this giving you a Windows crash dialogue, or do you get the Daz crash dialogue? Is that the very end of the log?
Weird but when I run as an administrator, it will works. I'm suspecting that it is BitDefender, but I'm not sure. Will run as an admin for now.
Running DS as admistrator can cause problems - it isn't a good fix, though it may suggest something about the root cause (though not to me, I'm afraid).