So, I got a Scarlett 2i4 recording interface to use with Cakewalk. The first day I installed it all was working well. The past few days though I keep getting an "unable to open audio playback device" error. It says the audio might be in use but even when I restart the computer and only run Cakewalk it STILL gives the error.
 
I tried Audacity and a trial of Cubase and also an old trial of Reaper and they all work perfectly with the ASIO driver but I hate using them. I've got ASIO selected in Cakewalk and sometimes if I change the driver to WDM, restart Cakewalk, change it to ASIO and restart again it works but obviously I can't do this every time I want to record something. I tried changing the settings in the control panel "sound" settings so that programs can't exclusively use the sound, that didn't make any difference.
 
As a sound card the Scarlett works perfectly, every other program records without any problems, just Cakewalk gives this error, but as I said, if you play with the settings and restart it then it works. It only works sometimes though. By the way I have the Scarlett selected under input and output devices and it's selected under playback timing and record timing master.
 
So could someone please help? This is the only recording software worth using in my opinion. Please help!
 
Sorry the post is so long.

Go into Options -> Audio -> Advanced and check the box that says "share drivers with other programs".

Thanks, I just gave that a go but it didn't change anything. It's giving the same error. I tried playing the track without restarting and restarting the program. I restarted windows too and that didn't work either. I honestly have no idea where I can go from here or why it stopped working to begin with. I've changed nothing since installing.
 
What I can't understand is why sometimes it works and other times it doesn't. Sometimes windows boots, I run Sonar and it works, other times it gives that error that the audio is in use even when nothing else is running. By the way I'm running Windows 7 64bit.

I have a similar issue with my Layla 3G unit - sometimes I have to shut down and start a second time to get it working, although it sounds like your problem stops you more than mine stops me.
 
Did Sonar 7 work properly with the interface you were using before the Scarlett?
 
In your Windows Device Manager, do you have more that one sound device (another one besides the Scarlett)?

Yeah, this is really bad now, it hasn't worked at all today. This is the first interface I've ever had, I used to just plug an old mixing desk into the line in on an old soundcard.
 
When I look in device manager there are a few other devices, one is the TV I have this plugged into, another is the other monitor I have and then there's the onboard soundcard. I have all these disabled in the sound options in control panel though, only the Scarlett is colored, the rest are black and white with "disabled" written under them.

From what I understand versions of Sonar that came before 8.5 can be a bit unstable on Windows 7 or 8.1 64 Bit. It was really a Window XP 32 Bit version.  I think if you look in the Cakewalk Knowledge base they state something about it being "untested" on Windows 7.
 
I would download and try the Sonar X3 Demo to see if this works for you. 
You can upgrade to Studio for less than $100 when they have a sale. 

I actually tried the Sonar X3 demo and it did exactly the same thing, the same error and eventually crashed while looking through the options menus. How come every other program works but not the only one I want to use? Ugh. All other programs are lacking in some way that Cakewalk isn't.
 
 
 

sock monkey
From what I understand versions of Sonar that came before 8.5 can be a bit unstable on Windows 7 or 8.1 64 Bit. It was really a Window XP 32 Bit version.  I think if you look in the Cakewalk Knowledge base they state something about it being "untested" on Windows 7.
 
I would download and try the Sonar X3 Demo to see if this works for you. 
You can upgrade to Studio for less than $100 when they have a sale. 

I just tried X3 again and it showed a new error, something about "the following driver isn't supported" then a little list with "Focusrite USB 2.0 Audio Driver Output 1" and then the options to "disable" or "use anyway". If I click "use anyway" it just shows the error over and over until I click "disable".
 

There are properties in Windows to give exclusive control to software. It is possible Windows has seized the Scarlett on startup. On my machine I have onboard audio enabled and explicitly set to default. With both onboard audio and the Scarlett online to Windows, if the onboard audio is default, reassign it to the Scarlett, then explicitly set it back to onboard audio. The other possible solution (probably preferred for your case) is to uncheck both exclusive options in the Windows properties for the Scarlett.

If the Scarlett 2i4 is used for both Windows audio and SONAR make sure the sample rate in Windows Control Panel properties for the interface and SONAR preferences are the same.