If the new (wrong) filenames are something like the following, i.e., have extensions, but the wrong one:
filename.jpg
-or-
filename.psd
....you could overcome the damage by engaging the PS rename function. (Not to worry... it won't hurt this time. :))
* From the dropdown menu in the 1st box, choose "document name". * In the next box type, .jpg (or whatever the original [correct] file type extension was). * OK
PS will take the full file name, e.g., filename.psd, and append ".jpg" to it, resulting in filename.psd.jpg. Not pretty, but easy to do and functional.
If what you have now is file names without extensions, e.g.,
filename1
filename2
filename3
....the above will not work. PS will not be able to "see" the files from the rename dialog in order to rename them.
================
Plan B considerations:
If the above method won't work and the number of files is relatively small (your call on what that number is), Open as... [original file format] or manually correcting the extensions via Explorer are viable alternatives. If there are "lots of files,' these methods could take a long time.
If time is an issue or you would prefer a fully automated method, here's another option to consider. Download/install a low cost (or free) file naming/renaming program that will undo the damage quickly - like in about 3 seconds.
I use "Bulk Rename Utility" available for download here: <
http://www.bulkrenameutility.co.uk>
There are many programs of this nature available. google:
The Rename
for a popular and highly recommended program or
file renaming program
to get a boatload of alternatives.
Programs of this nature have options and flexibility far beyond what's possible with the built-in PS functionality.
IMPORTANT: Practice on a folder of 3-4 "practice files" copied from the ones you want to fix before applying the corrections to the entire folder.
================
Finally, something to remember: Always populate the last box among those in the PS rename dialog with either of the "extension" options from the dropdown menu. This tells PS where to put the file extension.
Good luck on the file recovery.
~Danny~