Excel file renamed, changed to text tab delimted, lost tabs, unrecoverable?

I am trying to help my coworker.

He closed an Excel file he's been working on for days. He then opened "My Documents" from his desktop, right-clicked on the file name and renamed the file. And somehow now it is a text-tab delimited file. It had been an "Excel 97-2003 Workbook." He lost all but the active tab. We followed some tips to try to recover, going into the information tab and look for versions, or digging into "manage versions" but there is nothing there.

1. How on earth did his actions lead to the change in file type? :(
2. Any ideas on other means of recovering the file? or is it probably gone gone gone?

Any ideas appreciated,
Thank you,
AG

Unfortunately

Hello AGoins2010,

Unfortunately if the file's format was saved to a delimited file type, then your sheet is unrecoverable. This could have happened as a mis-click on the save screen (note that the .tsv file type is right next to the 97-2003 file type, which is probably how the error occured):

Really sorry I don't have a better answer for you. Hopefully it is not too much work to recreat what was lost.

Sincerely,

-Max

I was afraid of that - but

I was afraid of that - but pretty certain.

Thank you for taking the time.

He fortunately has backed up his system so he was able to retrieve a partial, but still lost a lot. I think the weirdest thing was that in the file folder it still had the Excel icon for the file type and said in the file type it was an Excel. Wouldn't have expected that combo. Even the attachment when he emails me the file says .xls
It was only when I attempted to "save as" I saw the text-tab distinction.

And renaming instead of saving as the way he did I could not find a way to change the file type - the drop down doesn't appear to change to .txt or .doc etc... He'd have had to type in a file extension by accident.

So I asked if he tried to use a period in the new file name. He didn't think so but wasn't 100% sure... thinks he might have tried to use a colon. I tested that and am still unable to recreate his issue - my test file is still an excel file with multiple tabs and formulas.

At this point I am washing my hands of it and moving one.
*shrug*

Again, thank you Max. :)