orangesporanges
(...) bump up the buffers in preferences, to give your processor and sound card a little "breathing room". If you have it set to a fairly low level( 64 or 32) try 128 or 256. (...)

 
I checked my buffer settings. I think they should be okay and not too low. Would anyone disagree or find some fault with the following?
 
I checked at Preferences > Audio > Drivers and clicked "ASIO-Panel..." which opened another window called "Line6 Audio-Midi Devices" with the following settings:
--------------------------------------
ASIO Client:
Default Buffer Size: 512
Default Bit Depth: 16 bit
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and then there is a slider with my mark (^) somewhere between "Extra Small" and "Medium" with no numbered values
----------------------------------------------------
Buffer Size:
| Extra Small |    | Medium |    | Extra Large |
                   ^       
------------------------------------------------------

About plugins:
We talked about that plugins can be the cause for problems. I haven't really understood how I would check them.
What I now did was opening a project with the SHIFT key pressed so that SONAR opens in safe mode and asks for every plugin whether it should be opened or not.
Is this the way to do it or is there something else?
I must say that I never got any feedback from SONAR about faulty plugins, neither with this safe mode approach nor with the checking at preferences > data > VST settings*. So I never got a real feel for how reliable this is.
Would SONAR detect problems with plugins with these checks or is it more likely that plugins pass these tests undetected and still cause problems later on in operation?
 
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* I am not 100% sure about the correct wording since I use a German language version of SONAR

Okay, I had another freeze/hang.
I was working with SONAR for an hour or little more with no obvious limitation when suddenly the teleport server error message popped up  (translation would be something like "The Teleport Server doesn't function anymore. The program is not working properly because of a problem..."). 
Playback stopped and SONAR stopped responding. I could still click here and there but there was no reaction and then the next error message appeared with something like "SONAR doesn't respond..."
So after a couple of minutes I had to shut it down like I always do with a click on "X" and a little waiting.
 
Starting SONAR again I got the same next error message as before "no audio devices for the current drivers connected to your system" and when I opened SONAR and went to preferences I could confirm that the fields were empty at
preferences > audio > devices and
preferences > audio > driver timing-master playback / recording
 
When this happened I was playing around with a plugin called 5orcery which didn't seem to cause any problems so far.
 
* So is this something worth searching for a cause or is one crash per hours just a normal number one has to be prepared for?
* And, is there anything I can do to fix the "no audio devices..." problem except for restarting the computer (which is what I now always do)?
 

Steffen Heller
Okay, I had another freeze/hang.
I was working with SONAR for an hour or little more with no obvious limitation when suddenly the teleport server error message popped up  (translation would be something like "The Teleport Server doesn't function anymore. The program is not working properly because of a problem..."). 

I think that would indicate a problem with a 32-bit plug-in in a 64-bit system. Plug-in bridging can work well but it is not always foolproof. This is why, for example, 64-bit Studio One Pro does not do bridging and requires 64-bit plug-ins. Some users have reported plug-ins that didn't work with BitBridge (what SONAR uses) run under J Bridge, and vice-versa. However, ultimately the fewer 32-bit plug-ins you use, the better.

Thanks Anderton. I must admit I didn't know what the teleport server stands for.
So it needs some kind of technology to make 32bit plugins work in a 64bit system. SONAR uses BitBridge to do that. The teleport server is some part of that and a teleport error message indicates that there was a problem with a 32bit plugin. Would that be correct, in its very simplified form?
I must admit I still have plenty of old 32bit plugins so this could be something I should put an eye on.