extremely bad crackling problem

I’ve been recording with audacity a lot and have done it for a while, but all of a sudden I am having a major issue. I am using The Beta version (unstable) on a Compaq presario r3000 running windows XP. I use a behringer Eurorack Ub2442fx mixer and use the Tape out as my source of audio (straight into the computer). Everything I’ve ever recorded on it sounds great for what I do, but while I was trying to finish up a song the other day, when I played it back, it had a bit of crackling to it. I figured it was nothing because with my experience with audacity I have grown to ignore minor crackles while playing back the whole project, because after exporting they’re usually gone. But this was not the case. When I exported it as a WAV, it was the wost thing on earth. Every time I had played a solo guitar part, the whole track crackled like it was too loud, but when I played it back on its own as just the solo it sounded fine. after re-recording all other tracks exept for vocals thinking I may have taken out too many mids, I tried again with the solo with a low distortion level and low recording level and it still caused the same problem. Without the solo the project sounds fine. but with it it makes the other guitar parts crackle a lot. I have recorded many solos in audacity with multiple other tracks just like this project, but I had used the 1.2.6 version. Does anyone know what is causeing this or a way to fix it? Should I go back to using the stable version?

The first thing that jumps to mind: Is that guitar solo track causing you to clip the output?

Trying turning all the tracks down about 6 dB and see how it sounds.

Turning all the tracks down 6db did the job. No more crackle or noise. Thanks a lot