I finally got around to trying sidechain compression from vocal bus to guitar bus to duck the guitars a little.  I did a little research and saw that the native Sonitus:fx compressor has sidechain capability so I tried that.  I added the compressor on the guitar bus, inserted a send to it on the vocal bus.  As soon as I hit play, the audio glitched then cut out.  I hit stop then play again but it remained silent, no audio at all.  Then Sonar crashed.  I restarted Sonar and tried this again but it immediately crashed this time.  I also tried this with the Sonitus:fx gate (also has sidechain capability), but same results.
 
I then downloaded a demo of the Waves C6 multiband comp to test, still getting crashes.  However, every few times I tried it again, Sonar didn't crash.
 
I know there is sidechain capability because I watched a couple demos of it on Youtube (it's how I discovered Sonitus:fx was a sidechain option).  What might be causing this, a plugin incompatibility or something?
 
I have Windows 10 64-bit, 3.50 GHz AMD FX 8-core CPU, 8 GB RAM, and Sonar version 21.13.00 BUILD 32 Newburyport - x64.

I've had this issue too. 
 
I just expect it to happen some of the time so before I insert the send to the sidechain I hit CTRL-S to save ;-)

MagicMike
I've had this issue too. 
 
I just expect it to happen some of the time so before I insert the send to the sidechain I hit CTRL-S to save ;-)

lol, ctrl-s is always the key!!!
 
Ok, thanks for the feedback and sanity check confirming that I'm not the only one having an issue.  Would you say this is a regular issue or infrequent for you?  For me it was crashing the majority of the time I tried to use it last night... well, it crashed EVERY time I tried to use Sonitus, but then just the majority of the time with the Waves plugin.
 
BTW, when it worked with the Waves C6, I loved the way it helped the vocal track cut through every so subtly.

Yes I've had crashes with sidechains as well. Lots of them!

It happens to me when projects become increasingly large,with a large plugin count.

MagicMike
It happens to me when projects become increasingly large,with a large plugin count.

This is how 90% of my serious Sonar problems start as well. Once a project gets past a certain size, and maybe a certain age, all kinds of weirdness and bugginess creeps in. I'm always delighted by how it works when I start a fresh project, but a few weeks later when I have dozens of tracks and synths and plugins and automation lanes and routing and whatnot, it becomes a huge PITA.

I've been unable to get a single sidechain compression send to work. Causes an immediate crash as soon as I click play. Doesn't seem to matter what compressor I try.

Hmmm it's the other way round for me. Most of the time sidechaining just works for me, but just occasionally I get an issue. I think the biggest issue I had was if I remember it rightly, I had addictive drums output across multiple tracks - so one channel per drum and due to some bug or limitation in Sonar, I was unable to sidechain anything on any other channels. I don't think it crashed though, just didn't work.

As others have said, it works fine on a fresh project but crashes a more developed file. And it's later when I'm in the mixing stage that I'm usually setting up a sidechain. Other sends are no problem, but sidechains crash n burn. I really like Sonar, but the inability to sidechain is a big detrament.

What I want to know is how much of this is caused by:
1) Too much software
I.e. people using their PC or laptop for things other than recording. If your system has lots of software running in the background, plus a fragged hard drive.
In other words do any of the people experiencing problems have a designated system for Sonar? Or are you also using it for other things too?
2) Not sufficient enough hardware
Slow hard drives, not enough cpu or ram resources.
In other words if someone installed Sonar on a fresh fast system and never used it for anything else except Sonar, would they still experience these problems?