I've had problems after upgrading to latest Windows Creator update with the audio playback not making any sound using my Tascam 20x20 interface. Tascam says there is a compatibility issue. You could try rolling back to the earlier version of Windows...Tascam suggested not updating until the bugs we're worked out by Microsoft.

I would be inclined to re-install Windows and Sonar and see if that helps.
In October we will be able to get the Windows 10 Fall update, so you might want to wait until then and do a clean ISO install of Windows 10.
Maybe you can borrow a different audio interface and try that. You can also set Windows to not update manufacturer's drivers automatically, and reinstall the original Line 6 Toneport UX2 interface driver if there is one, or reinstall the same or earlier interface driver with permissions for Windows 7 (or whichever Windows version was more prominent when your Line 6 Toneport UX2 audio interface was still being supported.) The fact that the Line 6 Toneport UX2 is no longer made and supported as noynekker stated, is enough to start thinking about replacing it. I notice their site says that USB hubs are not supported, in case you are using one of those.
 
A few apps might give you a clue. Maybe Latency Monitor or something, and Personal Software Inspector will let you know about out-of-date apps on your machine. 

mattburnside
Thanks for the reply, out of interest when you get the drops what is the actual RAM indicator within Sonar displaying? I know it's not the most accurate thing in the world but I'm loading pretty small projects when this happens as well.

In fact on the weekend had a guy recording some acoustic guitar with me so literally a guitar and a vocal track, un-mixed and no VST's still got the drop out on audio and briefly after that a delay to the headphones that despite getting 15ms total roundtrip made it impossible to use whilst recording. Also then got a complete crash of Sonar and headphones fine when re-booted. Windows and background all seems absolutely fine when Sonar dies too, I shall put another 8GB in this weekend and see if that helps though.

By default, the indicators in Sonar only show what Sonar is using, not what is being consumed outside of Sonar. You can change this setting, or use Task Manager to monitor your resources.
 
Regards,
Dan

I guess its up to the Line 6 Toneport UX2.
   
We have laptops with 4GB RAM and 1,6 GHz Dual Processor, recording simultan 4 stereo tracks of 4 tapedecks at 96kHz 24-Bit. (4 tapedecks per laptop). Starting SONAR needs a minute, but they don't have any dropouts recording 12 hours the day. All run ASIO. (audiointerfaces are Roland, Focusrite, M-Audio)
I would try:
- Change the USB-cable
- only !! ASIO
- When SONAR crashes its almost a (incompatible) driver problem with the audiointerface.
- Don't record to your system drive. Try an extern disc (for testing)
- Try another audiointerface !!
 
 
 

Something Craig Anderton mentioned a while back might be worth looking into as well. Does you graphics adapter have any HD audio options? You will find that in Device Manager under Audio Devices, if so disable them. 
 
How many other USB devices do you have on your system? I had a bad bottlenecking issue with my Focusrite because all my USB devices (mouse, iLock, MIDI controller) were using the same internal hub. Once I moved the Focusrite to its own USB port/hub all those issues went away and I noticed even my CPU usage dropped a bit.
 

Okay thanks to everyone for the input thus far, it's all very helpful and has given me some fresh ideas of my own for sure.
 
Okay so as expected ASIO is definitely what I wanna be using. DONE!
 
I have found my RAM is being read a bit weird as it's saying only 5.9 usable out of 8, I know you always have a little bit of loss but that seems high, image attached with Windows version here also. 
 

 
I'm pretty sure I had these kind of issues before the latest Windows update if I'm quite honest so I don't think it's the particular version causing conflict. Could be more hardware related or a simple setting I'm missing.

I have thought about replacing the Toneport recently but would want something that could potentially give better results. I always want to be recording at 44100 and 24bit and any suggestions would be welcome, is there anything utilising USB 3.0 out there with 2 mic and at least one line input?

I have switched the indicators within Sonar to show system usage and again the processor indicates a lot of head room, I do have a hell of a lot of options with this processor for overclock also which are currently disabled whilst testing if anyone has any ideas on them settings.
 
To answer even more of you kind people, I'm not recording to the system disk, I have replaced the USB cable to the Toneport and also right now only have a keyboard, mouse and a TP link WIFI dongle on USB, everything else has been removed and all USB devices are on the mobo not hubs. I he disabled the HD audio under control panel so will test this again now after a reboot. 
 
Once again thanks for all your replies and help.

One more thing to add is that the Toneport has two settings that affect the round trip, the actual buffer size at the top of this and then the slider. Anyone any idea what the slider actually is doing? Fine tuning the buffer?
 
Image from current settings, also no change since disabling HD audio, still hanging and crashed since.


 
I think I found out that the memory is being used now as my graphics card recently went down. Obviously won't be helping but is certainly not the root cause as was like this when graphics were on a separate card too.
 
Thanks for the replies and to anyone who joins in with any info or suggestions.

If you are thinking of a replacement, a stable "low cost" audio interface I have heard great things about is the Focusrite Scarlett range - just make sure you get the number of inputs you need and away you go

Looked over the Scarlett range and watching one on eBay now. 

Just noticed after more testing this score on the SSD where Sonar is installed, these figures look awful??

The disc is not the reason why SONAR makes problems.
We use a network NAS for recording (digitizing tapes, vinyl ...) over LAN that records from 8 laptops at the same time. And 3 DAW copy data from this NAS. And we have never had dropouts or crashes.
For a buffersize with 128 you need a very fast disc.
 
Try -- for testing --- a buffersize with 512.
If the problem still exists (with 512 or 1024) then there must be any unknown problem with the drivers. It can be that the toneport has very poor drivers.