Playback goes out of sync after stopping recording

Hi all.

I’ve just recorded myself playing the rhythm guitar part over an MP3 backing track of Highway To Hell.

During recording it sounded perfect and my guitar sounded totally in sync/time. At the end of recording however when I play the thing back my guitar and the backing are in sync for say 5 seconds and then the guitar part gradually comes before the backing track (as it were).

I’m recording via Line In and have two stereo tracks - the MP3 in one and my guitar in the other.

Any ideas what’s up with it??

If the speed is drifting (as opposed to being the same amount out of sync all through), then it’s likely to be due to your sound card.
Sometimes recording at a different sample rate improves things (Edit > Preferences > Quality). If that doesn’t fix it you could try updating / down-dating the sound card drivers, or buy a better sound card.

What sound card are you using? Is this a laptop computer?