You dragged them to Recycle Bin, unless something weird indeed happened.

Anything else missing?

Are you able to see these files you've found using Excel, or are you only able to find them in Finder?

I found them in the trash. They are my business files. No way I dragged then in there. Only two were found in the recycling bin. Every year going back three years, for every project. Gone.

I've avoided chiming in - but the descriptions you are using on how you navigate, find files, etc. has me worried. Lots of advice, but I'm not hearing the kind of response that gives me comfort about where you are looking.

In hindsight it is easy for me to say back stuff up. But seriously, why are you not using a free online backup service? I have an online-cloud backup plus a connected external drive constantly backing my files up. I used to support a bunch of end users and saw people lose years of work when hard drives fail.

1) Are you using finder to look for files?
2) Does anyone else use this computer? Do you have a cat? Cats are evil, they do this sort of thing for sport.

One of my girls was complaining that her computer deleted files all on it own.

Told her it was not possible.

One day I hear her screaming bloddy murder.

Go by her desk and told her to retrace her steps exactly.

She recreates the file and then goes to save it in the "Temporary Folder".

I asked her why she saved it there.

She replied that she always saves her stuff to a temporary spot and then files them later so the temp folder seemed like a natural place to save things.

I then asked her if she was aware that the application she was using creates a Temporary Folder when it launches to store it's cache, undo and similar files and when she quits the application the folder deletes itself along with everything in it?

Blank stare.

Hey Don,

I went on to Finder and found some files but they are empty. When I go and click on them, the same thing appear on the screen. "could not find file". Could it be a bug that cause this? No cat in the house. Kids have their own computer.

No on line back up because I really don't know how and have never tried.

I think you'd better bring the computers to a local Mac repair guy, if you can find a good one.

I can think of a couple more things to try. 1. Shut down Macs and restart. 2. Disk Utility -> Verify Disk and Repair Permissions. 3. Re-install Office and try opening the files again. 4. Buy an anti-virus app and scan.

But honestly it is super weird that this is happening to both desktop Mac and notebook Mac. That is right? You are having the exact same problems on both machines - Excel files missing, mysteriously found in Trash, when you try to open them in Excel you get "can't find" message, and it started happening at the same time?

Normally at this poing I'd be suspecting corrupted files indicating impending hard drive failure. But on two machines at the same time?

BTW, are the hard drives nearly full by any chance?

It sounds like corrupt directory map.

The way a computer store data on a disc is it writes the files blocks on the disc. A file will span multiple blocks. They are not always linear or consecutive. A file can be scattered in pieces in multiple locations all over the drive.

Your computer has a file that keeps track of all the pieces and where they are.

When you erase a file you don't actually delete data. What happens is the name is removed form the map which allows new data to be written on the blocks that the "deleted" file occupies. So you never really erase data, you overwrite data.

If the map gets corrupt you can lose files because the computer can no longer find them.

Have you run disk utility repair yet?

My advice is that you not create, modify or do anything else that will write data to the disk.

The files are still there, just a bit lost right now. The more things you write to the disk the more likely you are to start overwriting them.

Yeah that's got me scratching my head also.

You have the Mac OS disc? You may (probably will) need it to repair the hard drive directory w/ Disk Utility. Read up on how to run Disk Utility, e.g.
The Repair functions of Disk Utility: what's it all about?

^This.

I think you should take the machine to the Apple store, make a genius appointment.

Thanks guys. Yes both the desktop computer (both macs) and lap top are doing the same thing (same files are missing). I am puzzled that it can happen to both. Again, my lap top have not been turned on in a month. When I discovered I can no longer access the file on my desk top a couple of days ago, I immediately check my lap top, because I store many of my files there. I suspect the files have gone the very same day. Yep, time to call in the big guns. It not worth screwing up more things as the files are important and I don't know what the hell I am doing. The hard disk is 25% full. John, I am tempted to try and perform the repair function of disk just to learn how things are done but I am afraid I am going to screw up more things.

Do corrupt directory map happen often? what causes it?

I can't think of anything that would cause that to happen to two separate machines other than you had some sort of cloud / syncing / offline backup service running that you were unaware of.

Were both machines purchased recently? Did they come with Mt Lion or were they upgraded to Mt Lion?

Click the Apple upper left and chose About This Mac. Just below the Apple logo in that window is a version number, what is it?

Mt Lion, by default, saves a lot of stuff, documents included to iCloud. Everyone has an iCloud account.

What happened sounds suspiciously like iCloud was enabled at one point then turned off. When that happens it removes the local copies.

Hmm, that sounds plausible - let's see what info look gives

Mac OS X verson 10.6.8- desk top

OS X verson 10.8.3 - lap top

10.6.8 ='s Snow Leopard and does NOT support iCloud

10.8.3 ='s Mt Lion and defaults to iCloud

Without having physical acces to both machines I'm stumped.

Apple store time.

Hmm, unless you had one of the old MobileMe / iDisk accounts on the desk top that got migrated to iCloud.

Did Office do an update on it's own?

What version of Office are you running?

Were they saved as .xlsx?

Yes. Office 2008