Try disabling your WiFi dongle while using Sonar.  That has been reported to cause issues on some systems.
 
Also, run the free Resplendence LatencyMon to analyze the possible causes of buffer underruns due to DPC latency, which can cause audio dropouts, even without any other system bottlenecks.
 
It will analyze your system for real-time audio and report processes responsible for causing audio latencies which result in drop outs.
http://www.resplendence.com/latencymon
 
If these suggestions don't help, then testing an alternate audio interface is probably a good next step.

Thanks abacab, not seen this tool before but I think we're gunna get along really well :)
 
Results to follow

So I'd be lying if I said I understood a fraction of this data I've collected with the latency monitor. Noticed when actually opening a project today for the testing though that it tookj around 4 minutes maybe more to open, again masking me think it's the PC itself and maybe not the Toneport although I want to replace that as well to be sure.

See results from Latency monitor below, has anyone any ideas what it all means? I mean there were no pops or clicks during these tests, also had 512 buffer with no WiFi dongle. As always thanks in advance.,

https://www.dropbox.com/s...tn/Conclusion.txt?dl=1



 

mattburnside
So I'd be lying if I said I understood a fraction of this data I've collected with the latency monitor. Noticed when actually opening a project today for the testing though that it tookj around 4 minutes maybe more to open, again masking me think it's the PC itself and maybe not the Toneport although I want to replace that as well to be sure.

See results from Latency monitor below, has anyone any ideas what it all means? I mean there were no pops or clicks during these tests, also had 512 buffer with no WiFi dongle. As always thanks in advance.,

https://www.dropbox.com/s...tn/Conclusion.txt?dl=1

DPC's (Deferred Procedure Calls) would be the most likely culprit.  A DPC from another driver ties up your CPU so that it cannot service your audio buffer in a real-time manner.  You need to determine what is causing this and correct it.
 
I would think that this would be a huge red flag given by the LatencyMon results:
 
CONCLUSION

"Your system appears to be having trouble handling real-time audio and other tasks. You are likely to experience buffer underruns appearing as drop outs, clicks or pops. One problem may be related to power management, disable CPU throttling settings in Control Panel and BIOS setup. Check for BIOS updates.
LatencyMon has been analyzing your system for  0:09:13  (h:mm:ss) on all processors."
 
This following site has some good latency troubleshooting tips, however their latency checker is not fully compatible with Windows 8 and up.  But the info provided here is still very good.  Some detective work will be required on your part, and some steps are outlined here to disable devices one at a time in device manager.
http://www.thesycon.de/eng/latency_check.shtml
 
Background information: Why drop-outs occur
 
"Processing of streaming data in real-time is a very challenging task for Windows based applications and device drivers. This is because by design Windows is not a real-time operating system. There is no guarantee that certain (periodic) actions can be executed in a timely manner.
 
Audio or video data streams transferred from or to an external device are typically handled by a kernel-mode device driver. Data processing in such device drivers is interrupt-driven. Typically, the external hardware periodically issues interrupts to request the driver to transfer the next block of data. In Windows NT based systems (Windows 2000 and better) there is a specific interrupt handling mechanism. A device driver cannot process data immediately in its interrupt routine. It has to schedule a Deferred Procedure Call (DPC), which is basically is a call-back routine that will be called by the operating system as soon as possible. Any data transfer performed by the device driver takes place in the context of this callback routine, named DPC for short..."

unfortunately for the Line 6 Toneport UX2 that's still very old though
 
This

Thanks everyone for the helpful comments, I've done some more testing and made a new user account on Windows as I've been struggling with some other things too. Certainly has helped in the project load times, the opening project bar now appears straight away instead of sitting with not responding for a long time.

So just about to re-install Windows 10, pretty sure the only things I have altered were things from a guide on here for preparing PC for DAW, I know each case is unique but I'll see if I can find out why the hangs and report back. 
 
The long painful re-install process ;(

Cactus Music
unfortunately for the Line 6 Toneport UX2 that's still very old though
 
This

 
It may be old technology and not the best sound quality, but I used one of these from 2007 to 2016 and never had any serious issues with it. In fact I still use it sometimes with my laptop. It works well as a portable device because it's so lightweight. I'm certainly not ready to discard it yet.

As always :  Motherboard Chipset drivers : http://support.amd.com/en-us/download
 

But I see your using Windows 7. 
One of the best way's to trouble shoot is to swap out potential troublemakers and see what resolves the issue. This can be a simple as a bad cable.
Not everyone has 2 audio interfaces sitting around but a trip to a local music store I'm sure they would be happy to let you try an up to date interface to see if it solves the issue.
Good reliable ASIO drivers are super important to Sonar. And ones that have been optimized for windows 10 might be the case here.  

So I replaced the Toneport UX2 and things went from bad to worse.
 
Got a brand new Focusrite Scarlett 2i2 and the round trip time is up, crackles are increased and processor useage display in Sonar seems to be sky high all the time.
 
Drivers up to date and everything I'm not using has been disabled, anyone experience with the 2i2 and any quirks with Sonar I could be missing?
 
Thanks