I just installed Sonar X3e on a new computer (Windows 8.1, MBox interface) and now every project, whether it's an older one that never had problems or a newly created one, plays back at a faster tempo and a higher pitch than it should. It's almost like a Varispeed effect on analog tape.
 
Getting more specific - when recording MIDI data on a MIDI track, let's say I play an A. It shows in the Piano Roll for that track as an A. If I set the output of that track to an external hardware synth, it plays back as an A. But if I record the output of that synth to an audio track and then play it back, it's more than a half step higher in pitch. If I set the output of the MIDI track to a soft synth within Sonar, it plays back with the pitch shifted up. If the tempo of the project is set at 128, it plays back at about 138. I checked all of this against an external tuner and metronome. 
 
On projects with multiple audio tracks and soft synths, the tracks play back in tune and in tempo with each other. The entire project is sped up and pitch shifted.
 
I've never had this problem before, so I'm at a loss. I'm probably going to call Tech Support, but I thought I would post it here in case anyone had an idea about it. It seems like it might be an issue with Melodyne and/or AudioSnap, but it happens on projects where neither was used.

Could it be a Sample Rate issue?

jb101
Could it be a Sample Rate issue?

All of this stuff was recorded at 44.1/24, and those are the global settings in Sonar. So I don't think so, but I could be wrong.

What audio interface? If it has a console application, check the clock setting. If you're running WDM driver mode, try switching to ASIO. Does the status display show the project is 44.1?

Whoa! I have been having exactly the same problem with my brand new Windows 8.1 rig and my M-Audio Fast Track C400. I first noticed something was amiss when YouTube and other embedded videos were playing fast. It wasn't a video setting, e.g. 1.5x speed, it was just a little bit faster, enough to make people sound a little bit Smurfy. At first I thought it was a Flash issue and uninstalling it seemed to fix the problem, then it came back again. It would happen quite randomly. 
 
Then I started using Sonar X3e, and noticed a similar thing with a project I had been working on. The tempo is 104 but it started playing back faster than that. At first I didn't notice and indeed like an idiot I was sitting there kind of enjoying the faster tempo. Then it slowed back down to normal speed and I thought, what the hell is going on here? I don't have an external metronome but I did check it against a few online metronomes, with various results. 2 I tried showed that the project tempo was indeed too fast, but a 3rd played at the same tempo. However I have no way of knowing if the problem randomly went away when I tried the 3rd metronome, how accurate these online metronomes are to begin with, or whether or not the same problem which was making audio play faster would also affect these metronomes. 
 
The now time in Sonar isn't out of sync with the audio. It passes over bar divisions right on the beat of the music. So to all intents and purposes, everything is alright in Sonar. You wouldn't notice unless you were intimately familiar with how the project should sound (or if you happened to be listening when it slowed back down to normal speed). 
 
I was honestly too embarrassed to bring this up on the forum because I genuinely thought I was going mad for a while, and couldn't find any other reference to it. I spoke to the guy who made my rig (Jim Roseberry - it's a hell of a rig by the way, beautifully put together and an absolute beast ) and he suggested that it might well be the interface (or the Windows 8 driver) and that I should try things with the onboard audio for a while to see if the problem goes away. I haven't had time to experiment with this yet, maybe this weekend. I'm bracing myself for the possibility that the latest M-Audio driver is just not as Windows 8 compatible as it claims to be, and that I might have to buy a new interface that is. 

brundlefly
What audio interface? If it has a console application, check the clock setting. If you're running WDM driver mode, try switching to ASIO. Does the status display show the project is 44.1?

In my case, my interface clock source is set to internal and the sample rate matches the project. 

Something's getting hold of the clock rate and switching it to 48kHz. 48/44.1 gives a ratio that's between a half and a whole step high - very close to the OP's estimate of 138 vs 128 BPM. Normally, SONAR would recognize that the clock rate didn't agree with the project rate and throw an error on starting the transport. Sounds like there's a driver issue where the clock is running at 48, but the driver is reporting 44.1 to SONAR.
 
EDIT: Make sure your Record and Playback Timing Master settings are referencing the right driver.

brundlefly
What audio interface?

 
MBox, as I said in the first post. 3rd generation.
 

If it has a console application, check the clock setting.

 
Internal.
 

If you're running WDM driver mode, try switching to ASIO.

 
It's on ASIO.
 

Does the status display show the project is 44.1?

Yep. I'm at a loss.

Hmmm... I seem to recall seeing some threads about clocking issues with AVID interfaces in SONAR.

brundlefly
Something's getting hold of the clock rate and switching it to 48kHz. 48/44.1 gives a ratio that's between a half and a whole step high - very close to the OP's estimate of 138 vs 128 BPM. Normally, SONAR would recognize that the clock rate didn't agree with the project rate and throw an error on starting the transport. Sounds like there's a driver issue where the clock is running at 48, but the driver is reporting 44.1 to SONAR.
 
EDIT: Make sure your Record and Playback Timing Master settings are referencing the right driver.

They are. The only other possible explanation is that I've got an Eleven Rack hooked up to the MBox via S/PDIF - I need to check the clock setting on it. But since it's powered off and the MBox is set to Internal, it shouldn't be having an effect. I've got a bad feeling it's the Avid driver not playing well with Windows 8, in which case I'm screwed until they fix it.