To troubleshoot this kind of problem thoroughly really requires access to the computer, or at least you'd have to provide more specs -- platform, OS version, RAM, HD/SSD capacity, free space, etc.. It could be a lot of things -- corrupted audiofiles, a corrupted Live Set, corrupted Live Preferences, a corrupted copy of Live, a corrupted System, insufficient RAM, insufficient free HD space on the startup disk (which can cause other types of corruption), application/OS version issues, etc, etc.. Of course it could just be one of those inexplicable computer glitches that comes and goes, but if it's reliably repeatable, then you'll have to troubleshoot to try and pinpoint the cause, or at least identify the specific circumstances under which it occurs.. Did you make any changes to your setup just prior to the problem appearing..?
Some general troubleshooting steps might include..
- try importing the audio into a different Live set or (a copy of) an existing Live set that hasn't had any previous issues
- try importing different audio files (to various Live Sets), in case the problem is a corrupted WAV file
- try importing the offending audiofiles into another DAW to see if the issue is specific to Live or to the audiofiles themselves
- try running Live as a different (temporary test) user, which you'd create in System Preferences
- try turning off WiFi and other applications when running the the DAW (Live)
- check to make sure you have at least 8GB (ideally 16GB or more) RAM
- check to make sure that at least 20% of the startup disk is empty (free space) at all times
- try blowing out Live's Preferences
- try re-installing Live
- try re-installing the OS
If you're on a Mac, Apple tech support can sometimes be very helpful with this kind of thing, though they'll probably insist that you re-install everything -- in that case you should be sure to have a bootable backup (which you should have anyway!) if/when you do that, just in case..