Extensions disappearing in Bridge.

Hi, @Molly33244088y6h0, I'm not fully sure how this happened, but I do have a potential idea. FWIW, this has happened to others. If you look at the screenshot below, please note the section marked out in red. Now, I'm not saying you did do this, but if you'd have done something like this, it could have caused the problem. Note that the section in red is currently empty. It is possible for some people to think, "Gee, there's nothing that I can think needed to be added there, so I'll just delete that section. Unfortunately, that's where the file type needs to go. If that is left there, the file type will remain the same, but if you delete that, the process will delete the file type.

Again, I do not know if this is what you did, but it's the kind of thing that can cause these issues. Fortunately, there should be an easy solution. Read on!

The big issue is what kind of file were these. If we're in luck, they were all the same kind of files, for example, ".jpg" files. 

If they were all jpg files, run the Batch Rename again, but use these settings:

 In the first field, mouse-down on the left hand field aleft-hand "Current Filename." Leave everything else in red alone as presented.

In the Purple box, be sure the left side says "Text," and then on the right side, it shows ".jpg" and nothing more. 

I'd suggest putting (say) a half dozen images in a folder and running this just on that small group to make sure this works. 

Once satisfied it's working, you can do the rest of the images. (If you run this on the half-dozen you just did, then your file names would be "myfile.jpg.jpg" so do not run these again. 

When running things like Barch Rename operations, it's always a good idea to run a few first to make sure your results will match your expectations. In addition, keep an eye on the region in the Green Box for Preview. This shows what the current name is and what the resultant name will be. If the resultant name is not what you want, do NOT press the OK button until it matches your expectations. 

Let me know how it works out.