As a result of the recent upgrade to v15.4, I "lost" over 4,000 photos that are "Missing", according to LRc. I have followed numerous on line recovery suggestions, but have been unable to make any of them work. Have others experienced an issue?

Thanks for your responses.  I didn’t perform the action Victoria speaks of, so that can’t be my issue.  I only know I was working in LRc with no issue just prior to the upgrade and, after exiting and upgrading, I signed back in and noticed this data loss.  I exacerbated the problem by not having adequate backyp.

Hello, ​@Terry B B Wildlife Photos 

It would seem that (according to Victoria Bampton, the LIghtroom Queen) there is a problem with Lightroom Classic 15.4 that results in data loss. It could be this is what happened to you (or perhaps you may have a different problem). Anyway, Adobe is looking at it.

Is there a chance that you moved any of the folders containing the “missing” images outside of Lightroom Classic’s Library Module? Like with Mac Finder or Windows file explorer? If so, Lightroom Classic will see them as missing until you tell Lightroom Classic where they are now.

Are all the “missing” images in the same folder(s)? If so, right click on one of those folders and choose “Update Folder Location”.

​@Terry B B Wildlife Photos I’m sorry to hear that you have “lost” your images, but...

… unfortunately you haven't given us any information about your system and you describe your issue very rudimentary. Therefore, all proposed solutions are a look into the crystal ball.

What exactly you’ve done? 

What do you mean with “Missing”? Are the images include still in the catalog and Lightroom sign these with an exclamation mark?

Where are the original files stored? Internal or external drive? If external, is the drive connected correctly?

What do you have done to solve the issue?

I’ve update my Lightroom Classic with a catalog that includes approx. 70k images on yesterday. 

The update process runs without any issues.