Connect the audio interface only to USB 2 ports.  If you're already doing this, try different ones.  Right-click, Run as Administrator when running Sonar.

Thanks..hi Kenny...yes Focusrite gave me very good support but I could see they were running out of solutions,
It could only happen to me !

They were even going to try to locate Sonar 7 Producer ( as per mine) for test ...but as the purchase shop offered to refund me (Fairdeal Birmingham) and I had lost confidence in the Scarlet, I took them up on it and sent it back for a full refund...great service from them so I told Focusrite not to bother and thanked them for their help.

I'll try the administrator...I remember that once caused problems when I tried to register Sonar. Thanks...

I also found that increasing buffer size in ASIO panel made things a whole ot worse.

Couple other things to try:
 
1) Make sure your USB audio interface is the only device plugged into that particular hub.  It can be difficult to see which devices are on which hub without a lot of right-clicking and memorization, but a quick search on "USB Tree View" will solve that.  This is especially important because you don't want your audio interface and a power-hungry USB device (ie wi-fi) on the same bus.
 
2) I have found some terrible MIDI controllers to be complete offenders to my audio interface if they are setup wrong or are malfunctioning.  A recent incident with a new USB MIDI Keyboard controller caused me to return it as I was experiencing problems with my audio interface with it plugged in.  I replaced it with another USB MIDI controller and the issues went away.

In you other thread I think I recommended downloading a demo or even purchasing a newer version of Sonar. 
i beleieve Artist can be up and running for under $20. 
I would not expect software from 2006 to run perfectly on a 2015 system. 

It's too bad you sent the 2i4 back as I think with all the latest software and drivers you would have no issues just like thousand of other using the same set up.
Note: today Musicians Friend is having an hourly sale. My guess is at one point they will feature a Tascam interface for under $100. 
http://www.musiciansfriend.com/stupid?src=3TP5HUB
 
 

Rarecomponent123
Thanks..hi Kenny...yes Focusrite gave me very good support but I could see they were running out of solutions,
It could only happen to me !

They were even going to try to locate Sonar 7 Producer ( as per mine) for test ...but as the purchase shop offered to refund me (Fairdeal Birmingham) and I had lost confidence in the Scarlet, I took them up on it and sent it back for a full refund...great service from them so I told Focusrite not to bother and thanked them for their help.

I'll try the administrator...I remember that once caused problems when I tried to register Sonar. Thanks...

I also found that increasing buffer size in ASIO panel made things a whole ot worse.

Rarecomponent123, 
I'm glad to hear that you took the actions you needed to take w Focusrite. At least having done that , it put you in a much better position to do what you chose to do …
Just so you know , I much prefer using PCI over USB …
I have 2 PCI cards that I'm gonna end up using when I pick up a desktop ….
I sort of got forced into having to pick up a couple of USB cards due to using a Win 8 lap top and an i Mac..
the 2i4 has nice sounding pre amps and it is portable …my thing worked out OK w Focusrite so I'm gonna keep that card .
Since you already have a PCI card , what is stoping you from installing it in your system ? is you computer is a desktop ? if it is , all you really have to do is install the drivers first ( w out installing the card ) then install the card in an available slot …disable the on board sound and use your card as the main source of sound…if you have a lap top please disregard ….
then the next thing that you will have to do is figure out a way to monitor what you record in real time …
to do that all you may need to do is pick up a cheap Behringer mixer…used new it doesn't matter as long as it is in good working condition ….
A simple setup and the way I used my desktop went along these lines…
for midi recording I would just plug in my keyboard or midi guitar into the midi input that was on my PCI sound card …from there my midi  went  into SONAR and what ever VST synth I happened to be using …
now heres the important part …I took the 2 main outputs from my sound card and sent them to the little mixer.
that went into the input of the control section of a little Behringer mixer I  had …then I took the out put section of the mixer and sent that out to my studio  monitors …this little mixer that I had a little button where you could 
mute the speakers if you wanted …it also had a headphone jack , w a separate volume control for speakers and headphones..the whole premise is simpler than it sounds….( I'm not the best at explaining things scook is …lol) 
in a nutshell …you record all your midi and audio straight into the sound card  
(for audio you may need to boost the signal into you sound card via a little pre amp ) 
for latency free monitoring ( if there is such a thing )  you listen to what you are recording through the mixer…
I'm sure somebody can explain it better …for now that's my take on it …
 
Kenny

Thanks...I know my Sonar 7 is now old but I'm 100% happy with it...it could well be the problem as you say...please please don't say it's got to go ? I cannot face new software complete with a whole host of new problems....in fact I was happy with Sonar 5 ....!

But I guess I'll consider upgrading Sonar if only to potentially alleviate the glitches I'm getting, (hopefully)
Logically it's the thing Focusrite homed in on as perhaps being the problem. Wonder if anyone else is running Scarlet interface with Sonar. 7 producer ? (And windows 7 premium )

Yes I've tested all my USB connections and interactions etc...one thing I did find is that a certain cheapy hub I once had used to freeze my PC during boot up for a long time...now that's gone it boots as it should.

kenny ...that's a solution ! I'll keep that in mind. I do have a spare Mackie mixer ... Thanks ..

But no...I don't have a PCI card..was going to get one ...an EMU 0404 off e bay ...but wasn't too sure about it...
Only about £60...new...but I did dislike the tangly midi/audio in-output connections hanging off cables.

You know ..it's probably laptops caused many interface problems ...no room for a dedicated soundcard etc..?

So what are your PCI cards ?

 
Rarecomponent123,
 
the two PCI cards that I have are kinda old school , 
On my XP machine running SONAR 6 PE I have a Delta 1010lt …with that card , Yikes talk about a tangled mess 
99% of all the music in my sig was done w that card….
Then I have an Audophile 192 …I love the tone of it …..I currently have that card packed away as my spare …
In my situation , the most logical thing to do would be to pick up a desktop and then drop the 192 into it .
 
Take what I'm about to say for whatever it's worth… I seem to be outspoken to a fault 
I happen to think that a persons connection with creating and expressing music is a very personal thing ….
One size simply don't fit all .What works for me might not work for you , what works for you may not work for me 
…You get the drift ..
I ran SONAR 6 PE on XP right up until about 2 years ago …
I liked SONAR 5 Studio so much that I used it primarily for midi and creating arrangements  ….
once I had something I liked , it was then taken into S..6 PE and completed there and combined w my audio tracks.
 
What I'm saying is ….You dig SONAR 7 ..that is good enough for me….trust me I know ….
I think the important thing to consider here is "what will it take for you to get up and running , with what you have already  "
What do you reasonably need to " acquire " so you can express yourself creatively and make music again ?
 
You happen to be in a good position because you already have a computer a mixer and SONAR 7 …
Part of the thing is you are  getting feedback from folks that have moved on from SONAR 7 a long while ago and in many cases some of the folks around here may have had more funds to put into upgrading their hardware and software….
to the credit of many of them I'm sure they are motivated by helping you avoid some of the mistakes they may have learned along the way ….
 
If I was exactly in your shoes I would probably stay focused on researching what sound card would meet my current needs in spades …in addition to  that I would try to future proof it a little bit by getting a hold of a card that has drivers that are stable in W 8 and 10 ready ….then balance the book and try to swing it ….
 
if you happen to find "something dirt cheap w good features"  because it is not supported past W 7 , then that may be just an OK placeholder card until you can swing a better card that will more than meet your current needs.
 
good luck , 
 
Kenny
 
 
 

Thanks again Kenny....some good Info there and I appreciate your time.

I may upgrade my Sonar 7 ...why is it I always think " this time there won't be any problems " ...I always do...alas.

I found a bug fix for Sonar 7 and ASIO particularly on the STOP feature on the cakewalk site ...that was THE problem I was getting...but I've spent over an hour trying to download it ...Cakewalks site is too security For a simple bug fix download ....I cannot even get past the account log in so far. It's saying my details won't tally with the forum...what ?? !
Im sick of filling the boxes again and again and again...blanked out every attempt.

But going back to the Sonar upgrade ...as I only record an analogue synth one track at a time ..no record monitoring etc...I'm wondering if a basic version might do ?

I may make a new post for some advice...I don't want to spend on uneccasary features.

Someone said even if I put a PCI card in I will get the same problems ...that's nagging me...hence the thought about upgrading Sonar 7 ...
Anyhow that's where I am right now...I think maybe Sonar upgrade before PCI card ....maybe ?
Hope yours go better than mine !!