Those files were on your Harddrive or CF card?
They were on my internal hard drive, but my CF card is having trouble too since I saved sounds A through Z in a "DRUMS FOLDER" and went to load it, it said "END OF FILE". When I checked inside the folder only sound A through E were in there.. LOVELY!

Did this just happen suddenly ?
Yes, when I started using the machine it worked fine, I installed the Hard Drive and CD-ROM and everything was great for 4 months. 2 weeks ago everything started to deteriorate inside so to speak.
Do you save to a new folder every time or just replace the existing one with new data?
My overly anal-retentive obsessive compulsive Virgo habits force me to put everything in a seperate folder alphabetized including the date it was created.
Do you create a new file before working?
At first no, I didn't know what I wanted to name the folder before I started working, but after my mpc2500 started freezing whenever I went to NAME A FOLDER, I then began to create folders before I started working. By the way.. how that worked was: I had to create the folder>name it>the machine would freeze>I restart the machine>the folder I made was still there>after I make a beat save it in the folder.
Why do you think it happend?
I have no clue, see I played piano since 12 and brought records to engineers when I was 13 and tell THEM what to do with it beacuse we were now allowed to touch these peoples equipment. Years later I got my own ASR-10/mpc3000, read the manuals, and made tracks and co-produced major songs. When something goes wrong we take it to Rogues or Armen's shop in the city and he tested it and fixed it. Thats how it worked. However for me to understand what goes wrong with files and drives is technical and what the computer programming students at school know or people into elctricity itself understand. I can't bring myself to understand it, I only have colors, beats, and samples in my head.
How is your file tree set up and what harddrive do you have installed?
My file tree after ROOT is: each folder is named according to what it is. "Drums Sounds"(and source) withing that is the "kits" I constructed, other folders are "Loops", "Sampled Sounds", "Tracks" and within that is the song named and the dates it was done. not sure if that explains the "tree" but hopefully you can imagine it. The hard drive I have installed is the 80GB Toshiba that was Tested by Akia on their website.
I love music..hate computers.. imagine that!?