After I installed Vectorworks 2018, my Anaconda python installation could no longer use Qt, so python apps like spyder and matplotlib didn't work. I found out that, for some odd reason, Vectorworks 2018 puts the Qt dll files (QtCore.dll, etc...) in the Windows/System32 directory, which overrides the ability for python to use the PATH environment variable to find and use its own installed Qt DLLs.
I moved the Qt DLLs from the Windows/System32 director into the Vectorworks2018 folder, and that seemed to fix the problem. Both Vectorworks and my Anaconda python distribution work properly now. I had to do this again after the most recent Vectorworks Service pack update. I would strongly urge Vectorworks to not use the Windows/System32 directory for DLLs that can interfere with the operation of other installed programs. Just thought I would post this here in case anyone else runs into this issue.