Pentagon Goes Silent on Sonar 8.5PE x64

I'm running into a frequent problem with the Pentagon soft synth ever since upgrading to Sonar 8.5PE 64 bit.  Initially everything is fine as I browse from preset to preset and play my keyboard to audition different sounds.  Eventually I switch to another preset and Pentagon stops making sound.  But Pentagon doesn't completely lock up.  The user interface still works because I can switch to different presets.  The dB meter in the track still moves up and down as I play my keyboard; but no sound is produced. 

Everything else in Sonar still works.  It's just Pentagon that stops making sound.  It appears that the problem is connected to specific presets in Pentagon.  If I close and reopen Sonar, I can get Pentagon to work as long as I avoid the problem presets.

I've searched the forum for a similar problem but haven't found a solution.  Any help would be appreciated.  Pentagon is my favorite 'synthy' soft synth.  I'd hate to lose access to it, so I'm hoping the CW clan can help.


My specs:
Sonar 8.5 PE x64
Windows 7 x64
Edirol UA-25EX
Running Sonar as an administrator.

That's an interesting idea.  I'll take a look this evening and will reinstall the old version if possible.

Since so many people have had problems with Pentagon, especially on x64, I've been assuming that either:  1) I'm out of luck and I should just forget about Pentagon, or 2) there's some mysterious system setting or procedure that will magically correct the problem.

Anybody else have this problem or something similar?

I'm using Pentagon version 1.4.  I have no way of knowing what version I had installed in Sonar 8PE 32 bit.

The situation with Pentagon baffles me.  Pentagon has caused lots of crashes on my old and new DAW setups.  I've switched computers, opertating system, audio interface, and Sonar version.  I even switched from 32 bit to 64 bit. 

From my experience, Pentagon is unstable under a wide variety of conditions.  I'm surprised that there aren't more people complaining about it.  I'm guessing that most people give up on it, so the struggling user base is small.

Search the forum. I had this problem about a year ago or so and there is a post in the forum that tells you how to fix it. I don't remember what I did.