I have Sonar X3 e and it is incompatible with the Arturia V3 VST's.  I have the VST2 versions of Arturtia installed but Sonar isn't seeing them.  How do I make them appear? 

I just tried out a couple of the Arturia Collection 5 VST3 plug-ins in X3 and they worked OK. I know there were some issues with early VST3 releases in Collection 4.
 
As long as the VST2 plug-ins are installed somewhere in the SONAR VST scan path set in Preferences > File > VST Settings and scanned, the plug-ins should appear in the synth plug-in lists. I do not believe the VST3 migration settings affect Arturia plug-ins. If they do, those settings on the same Preference page as the scan path info.

I may have misread the OP. If this about a version of Arturia plug-ins older than Collection 4 I cannot help except to say, if a vendor identifies their plug-ins differently, SONAR will pick up all the version. Both Arturia Collection 4 and Collection 5 VST2 and VST3 show up as separate plug-ins in SONAR.

Which Arturia plug's are not working for you?

I have the V3, V4 and V5 collections, the early VST 3 versions of their synths did have a problem in X3 but I just tested the Modular V version 3 which is VST3 in SONAR X3e Producer, which I still have installed on my Secondary machine, it worked fine.

You could try removing the check mark from the hide Related VST2 Plug-ins in preferences > File > VST Settings.  This will show them both to you.

No my plugIns are Arturia collection V but They crash Sonar.  Sonar shows a fatal error.  They work in Reaper and Realband, I can save them and reopen those programs.  But I really want to use them to record in Sonar.  But its all of the Arturia VST3's.  and the v2 are not showing up even though they are in the Cakewalk VST folder.  

Thankx I got it to work by unchecking that setting.  Now I have to figure out which fx plugIns to use.  Thanks so much everyone.