James,
Are they saying that there *were* another 1000 items, but AC no longer sees those files on the disk and they are missing?
There is a critical issue here of whether there is a disk error or a corruption of the file system.
As a precaution - you should IMMEDIATELY run a manual backup of AC that INCLUDES Imported Items, Images - EVERYTHING.
You are going to want to write that to another disk *NOT* the one where AC currently resides. Turn ON all of the error checking and file verification steps, but don't upload it because it won't go.
You are going to also want to grab a copy of your backup from Thursday (or last one before Friday), because you are going to need it to determine the BEFORE list of imported Items, if it comes to that.
If you have another machine that can serve as your temp AC server, that would be your best bet to do next, because what you have to do next is determine if there is a physical disk problem, or just OS/file corruption. Testing that isn't going to work on a production machine.
There are tools we have used on the SMB/Enterprise side to recover files from corrupted disks - those work best if you take the machine offline until you are ready to recover so that minimal files are over-written, or further corruption takes place.
If the disk is bad/going bad, that has to be dealt with separately from data recovery.
Some questions:
What machine can you make the AC server for the next few days?
Are the server disks RAIDed?
Does your IT help have experience in doing data recovery?
Do you have a spare disk on-hand that matches your existing disk(s)?
I'm not a Doc; combat first aid is as far as I got, but we are trying to minimize the damage, prevent further damage while finding a path for you to continue to operate, then see what we can do about reconstruction.
I have also see where folks are ditzing around with the AC/Imported Items directory and inadvertently drag them somewhere else on the machine - it could be something that simple, just in case it is something that simple.
You've mentioned you have local IT folks, but if you need to reach out to a crusty sailor, feel free.
