Have performance issues same session different times

[bukemhed]

OK so a couple times I 've noticed that my audio is getting the pops and clicks during a certain session, but if i reload that same session (with no changes made or added) after restarting Ableton or the entire computer, then it runs smoothly. I have the same appplication(s) running in the background as before (or none at all as before as well). Can anyone explain why this is happeneing?