Raptor

I hope you folks can enlighten me. I'm not a techno wiz kid. I use LR Classic.I use a MacBook Pro. All my photos are on Master Photo Disk (blue). I use Carbon Copy Cloner to back up photos to two identical drives, red and black. I can read contents of all 3 drives with no problem. The blue drive is, I believe, corrupted. When I am importing lately, some pics will have an exclamation mark next to it....file damaged or cannot be found....I have used First Aid in Disk Utility several times. So. I wanted to use red drive. I cannot get LR to recognize this drive. I spent 2.5 hours on live chat with Adobe. The tech wanted me to import all the pics on the red drive into my catalog, essentially doubling its size. This did not make sense to me. Isn't there a better way?
And if I continue with this current storage and backup system, I am going to have to replace the blue drive anyway.
I hope you folks have a solution. Thanks for listening....reading.

traderjohn Loc: New York City

I am in the same ballpark as you when it comes to understanding the hows and the whys. Lightroom does not recognize those particular photos. You have done something foreign to LR. He wanted you to import those missing photos so LR knows where they are. Search past posts there have been how to's on how to solve your problem.

frankraney Loc: Clovis, Ca.

With light room closed, can you read the files ok with your file browser. If so, you have moved the files outside of LR. go back into Lightroom, select the files with the exclamation mark and repoint to the correct location.

mikeglaw

Since you have multiple copies, try reformating the drives, and then copying the good drive to the reformated drives.

Mike

Picture Taker Loc: Michigan Thumb

I would, first thing make another copy to be sure you still have 2.

refilman Loc: California

It may work copy the lightroom catalog to your internal drive, unplug Blue, and rename "Red" to be "Blue". (I assume the file/directory structure on your backup is the same as your original disk, or can be made to be the same.) How well this works depends on what else you've been using Red and Blue for, and (for all I know) what operating system you're on. However, I've done this successfully on OSX when all these disks are being used for is photo storage/backup. I actually do this regularly when my version of Blue needs to be replaced with a bigger Blue.

Alternatively, copy the missing files from Red to the right places (file/directory) in Blue. How to find the missing files? Do Library>Find All Missing Files (probably best done in Grid mode). How to turn this into a list of file names? There are a variety of methods described on https://community.adobe.com/t5/lightroom-classic/how-to-export-a-list-of-selected-file-names-to-share-with-a-collaborator-or-client/m-p/7346741 A little bit of light scripting can turn this list of files into a copy command from Red to Blue (I know this last point is one of those "less than a minute if you know the right stuff, and completely opaque if you're not a programmer" comments...)

Raptor

How do I do that?

frankraney Loc: Clovis, Ca.

You need to check "quote reply", as I did here, did we can tell who you are replying to.

Merlin1300 Loc: New England, But Now & Forever SoTX

Here's what I'd do.
First - CLONE your defective drive to an external HDD box (Sabrent) using Macrium Reflect (Free)
Buy a NEW disk drive (equal or larger capacity) for the Clone operation (SSD recommended, mechanical WD NAS certified {Red} otherwise)
Next - use a HDD recovery program such as Easus Data Recovery Wizard (paid - but inexpensive), or Recuva to restore all files possible on your EXTERNAL disk drive (again - I recommend the Sabrent https://www.amazon.com/gp/product/B0759567JT)
Once done and you've recovered all you can, REPLACE your old disc drive with the one you've just created in the external HDD docking station.
IF you have a significant number of images that were unable to be recovered - you may need to send your original HDD/SSD to a recovery/clean-room specialist for repair. This is NOT cheap.
In ALL cases - it is apparent that your data/images disk drive (Blue) is failing and needs to be replaced.
If you are not familiar with the above - you may need to hire a Geek.
-
OH HECK - - You have a Mac. Nevermind.
Back up your Blue drive to either your Red or Black drive. Then replace your BLUE drive with an equivalent or larger, then restore it from your RED or BLACK drive - which ever is most current. IMHO, your Blue Drive is is failing and needs to be replaced.