Adobe Bridge Find not working

Two things (and please, I have no idea who you are, or how much you know or do not know. I am only trying to answer your questions. So, if I explain you things that you do know, please understand, it's better to explain everything rather than assume you know all this stuff.):

#1) are you on a Mac. If so, have you given permission for Bridge to access your external drives, Desktop, etc.?

#2) Have you set Bridge's Find command to where to look?

Let me start with #2:

To the right of the search field is a dropdown menu icon. Press on that to verify where you want Bridge to search. If you want to be more granular, use the Advanced Search. Here you can go directly to external hard drives or specific folders.

 From the Advanced search, you can access recent past folders or, at the bottom, Browse.

If you browse, you'll see a standard OS window where you can focus on exactly where you want to search. Here, I've clicked on one of my external hard drives, and you can see from the arrow that's where I'm at. If I click on any of the folders within that window, that's exactly where my search will be focused. 

Once that's open, you can also narrow down what type of files you're looking for by searching using the Criteria

Here, using Name and Ends with, I can enter ".mov" and search for MOV files within any selected folder.

I hope this gets you started on how to find things using Bridge.

But, if you can't access external drives, you'll need to do the following.

So, here's #2:

This is not the fault of Adobe or anyone; this is Apple making sure that applications that have not been given permission to access areas of your computer cannot access those areas of your computer.

Here's how to do this using Sequoia, if you're using an earlier OS, the concept is similar.

Go to your Mac's Settings, and search for "security." That will get you to the settings that Apple uses to let you bypass their default "vault" protection. (This is a good thing.)

Starting off, you see this, note I have three things marked out.

Starting from the 2nd, Full Disk Access, if you select that, you'll see all of the applications that have been granted Full Disk Access. If you see Acrobat but it is not turned on, click on the switch on the far right side. If you do not see Acrobat, click on the "+" symbol on the bottom, locate Acrobat to add it, then turn on the switch.

Next go to Accessibility, same conditions as above.

Lastly, go to Files & Folders, this should already be set but depending on where it's located (such as a server), you may have to set this as well.

Again, all of the above may have already been done by you, but it's wise to check.