Traitement par lot - Bouts de fichiers détruits

Thank you for your answer !

I will try only changing this setting at first and update you whenever we tested enough files to consider this fixed (or not). 

It's not always so easy to spot what's going on when this happens, but the obvious (to me anyway) thing to try initially is to reduce the number of concurrent processes allowed. (Edit>Preferences>Data - don't go beyond 2) The reason for this is that batch processing relies on using Audition's temp files and the temp file system is, to my mind, rather 'fragile' at best, not least because on most machines, it hasn't been anything like optimised. Concurrent processes of the type you get with batch processing invariably involve juggling with temp files, and if these are in a location where the OS can get at them, then it gets priority - sometimes with strange results when other access is resumed.

Ideally your temp files should be given a space on a drive of their own, but for many users that isn't always so easy. What does appear to work reasonably well is an external USB SSD with a folder just for holding them.