Hi. Sometimes when we do our MRP regeneration, it doubles all the demand & supply on the reports. Has this happened to anyone? Does anyone know why it happens?

Thanks.  That scenario is very likely here and makes sense.

Yes, that would do it.  The first thing MR-F does is clear the file so it starts with an empty file.  If it can't clear it (because another user has it open) then it ends up appending to the existing records.  I can look into ways to prevent that from happening.