In reference to prog_head's question, UAD malfunctions on my system when used in the FX chain in the Pro Channel AND in the FX bin.
 
Unlike BlueRecording Studios, I am abandoning UAD for the moment, rather than Sonar. Several of the new X3 features have become must-have's for me.
 
UA support has indicated via email that they consider the UAD/Sonar problem a bug and it is on their list for fixing at UA, but they will not predict a time frame. For some reason, Cakewalk hasn't taken complete ownership of the problems, but they did say it has something to do with some things they're planning to address in future updates.
 
It's logical to reason that Cakewalk changed something between X2 and X3 that created the problems, but in my communications with both entities' tech support, UA is the only one saying specifically that they have it logged in their bug system and are working on a fix.

When X3 first came out the UAD problems were discussed at length with reps from Cakewalk who told us that there were some problems and were working with UAD to sort them out. Does UAD 7.4 which haas not been out long change anything for the better?

I bought the Bluecat Patchwork and started putting all my UAD stuff in that VST host which seem to fix the problem but at one point glitched out so bad I couldn't open my project until I uninstalled bluecat Patchwork.

I'm running UAD 7.4 and it hasn't fixed the problem, though it did clear up the problem with having to do a global re-enable of FX to get them working right after opening a project when they're in the standard FX bins.  I have also had UAD tell me they're working on it (but it doesn't seem to be a priority) and that Sonar isn't something they officially support.  My official CW support experience so far has been to check a bunch of things that were already setup properly (and which others in the forums had already mentioned).  Nothing from them about it being on their end or that they're working on it.  Hmmm.
 
As for workarounds, I'd say if you have the disk space, freeze your tracks once you get them the way you want them.  They keep their processed FX that way, and I believe you even get your DSP allocation back on the UAD card as technically it's 'bouncing in place' so that effect is no longer active in the project anymore until you unfreeze.  A good way to get a higher instance count of UAD in a project if you're already using a lot.
 
Hopefully they'll get it sorted out, just hopefully not in another upgrade I have to pay for that then leaves me other bugs to find and troubleshoot and work around.  It's been like that since v8.5 IMHO - I pay for bug fixes as part of a new release, but then I get more/new bugs.  The price of progress, I suppose.  I definitely found some must-have features in X3 or I wouldn't be wasting my time trying to find ways to work around the issue.  Any other suggestions, I'd love to know.
 
Just out of curiosity, anyone having this issue out there with absolutely no 32-bit plugs in your plugin list when using x64 version of Sonar?  I have 2 plugs that are 32-bit, but they're referenced in the plugin manager by their own path and all my UAD stuff is pointed to the 64-bit plugs under the Steinberg folder (as UAD suggested).  I'm wondering if a bitbridge server is being used for those 2 plugs I have and somehow messing with the UAD stuff.  When I get some time, I'll try removing those from my plugs list, resetting/rescanning and seeing if the issue persists.
 
Cheers

I've gone so far as to completely remove ALL 32-bit plugin's from X3's scan list, but the UAD/Sonar problems remain the same.

Here's UAD's latest support reply:
 
"I've heard back from our QA department and they have notated the issue and will be contacting Sonar with the information.  That said, since this ONLY happens with "Sonar Prochannel FX Chains" and not with standard inserts, and also appears to have broken between Sonar X2 and X3, it seems this is clearly a Sonar issue.
 
Since, as you noted, everything was working in X2, it indicates the plugin functionality is correct and something changed in how Sonar handles the Prochannel FX Chains in X3 which we don't have any control over."
 
This is more in line with my knowledge of programming - if Sonar's change introduced the issue & UAD hadn't modified anything, then likely the issue is on the Cakewalk side.  Now, to get any sort of official response out of CW...

Unfortunately, that response from UA shows they don't entirely understand the problem. They should know from my support request of almost 3 months ago that this does NOT only happen "with Sonar Prochannel FX Chains."
 
As I've made clear to UA, my problems with UAD and Sonar X3 are with UAD plugin's in the standard FX bin.
 
 

Cakewalk has long way to make X3 usable at this time if they are going to fixing minor and cosmetics issues {some color customization} and dont focus on real issues {UAD} and very important features {VST3 standard functionality}. I dont think it is so difficult to fix UAD stuff as in X2 it works perfectly.

BluerecordingStudios
Cakewalk has long way to make X3 usable at this time if they are going to fixing minor and cosmetics issues {some color customization} and dont focus on real issues {UAD} and very important features {VST3 standard functionality}. I dont think it is so difficult to fix UAD stuff as in X2 it works perfectly.

 
Nope... Now fully confirmed as a UAD issue.
 

Noel Borthwick [Cakewalk]
Its possible that this issue is also a side effect of the plugin chaining API. All versions of SONAR since 8.5 use this custom UA API that we implemented for them years ago. 
 
I was in touch with UA fairly recently about this and their response was that this API is no longer actively supported by them at the host level and only used by them internally now. I was also told that they would add a remedy from their end. From our side I have now removed custom UA chaining support from SONAR for the next X3 update so hopefully this shouldn't be an issue going forward.
BTW this isn't really specific to X3 technically - the only reason that you see a difference in behavior is because the UAD driver seems to be testing for a specific SONAR version and masking the error messages - which is why the some UAD warning messages started popping up in X3.

 
http://forum.cakewalk.com/UAD-aux-sends-disabled-in-X3-and-where-the-buck-stops-m2961478-p2.aspx
 
Pie anyone?

Strange that UAD asked CW to implement some function to work UAD, then they remove it from UAD drivers and dont tell to CW. This is very strange communication between big industry leaders...