I'm trying to use the Pentagon 1 synth. I dragged it to a track's effects bin, and up popped a message saying the plugin ("rgc:audio Pentagon 1")is "missing or improperly installed" on my system. But the .dll is there in the folder Sonar put it in. (Cakewalk/Shared DXi/Pentagon 1) And I have Sonar set to scan that folder on startup. I also re-scanned manually, but the synth is still not working. Any thoughts?

On my system, which is the x64 version of SONAR (same behavior in X1 and X2), Pentagon I will only load properly if I run SONAR as administrator (right click on the program's icon in Windows and pick "Run as administrator" from the popup menu).  When I try to run SONAR normally (which I do most of the time -- I don't actually use Pentagon very much), I don't get the exact error message you referenced, but it has similar meaning -- specifically, it says, "Failed to insert soft synth.  The synth may not be properly installed.".  If I run SONAR as administrator, though, Pentagon I inserts fine, both as a softsynth and in an FX bin on an audio track.  I don't recall having had this problem prior to using x64 (last time I used the 32-bit version was with SONAR 8 or 8.5, and I don't have either of those on my system at this time to check).
 
Rick

If you see both a file named P1DXi.dll and a file named Pentagon I.dll in the Shared DXi folder, delete the P1DXi.dll one.  Then move that folder to

C:\Program Files\Cakewalk\Vstplugins\

In SONAR, rescan plug-ins.  Perhaps that will fix it.  Please let me know.

@ RickPaul: Thank you. I ran Sonar as administrator, and Pentagon loaded properly. Not sure I understand why, and I hope they (I?) get this fixed so I do not have to remember this workaround. But mostly I'm glad it's working. Many thanks for your help.

Good call, RickPaul!  That's a better solution.  My suggestion won't require running as administrator.  However, I don't think Pentagon would be referenced by older projects, in that case.  Which would be bad.

You can also right-click the SONAR icon and set it to always run as administrator.

Thanks!

Hi Bill: I tried your suggestion, but it still wouldn't work. So I've left things as you suggested (moved the .dll etc), and then ran as admin, and it works. So while your suggestion didn't help, it also didn't make the situation worse. I'm not sure how to set Sonar to always run as admin. I've never used Pentagon before, so I'm not worried about previous projects. Thanks.

Looks like I spoke too soon. Sonar has crashed several time since I inserted that "working" synth.

Right-click the SONAR shortcut, choose Properties, and check this:

Rt click the link to sonar... Properties... Compatibility tab, at the btm, a checkbox that says Always Run in Admin mode... 

Thanks to both of you. However, now I'm really screwed. Sonar crashes before I can even get a chance to delete the synth.