Where did my lrcat go?

[Resoman]

Lightroom Version Number

15.5.1

Operating System

1. macOS 26 Tahoe

I came home from a trip at the end of August to discover that my iMac had suffered a hard drive failure, it wouldn't start. I took the Intel iMac and my Time Machine backup drive to my local Mac repair shop, where they replaced the hard drive but found that they couldn't restore from my backup drive because I had opened the drive on a newer M1 iMac which had somehow make the Time Machine backup useless on the iMac it had backed.
OK, I've bought a new M4 iMac and have access to the image files on the Time Machine backup as well as most other files, but not applications.
As I look at the backups on the new iMac, there is no Lightroom folder in the Pictures folder, so I don't have the last lrcat file. I have found some old backups where the Lightroom folder is in the Pictures folder, and have an lrcat file from 2019, that's the newest I can find.
I've installed a new version of Lightroom to my new iMac, but haven't imported any photos to it yet. Is there any hope (I doubt it) that I will find the lrcat file, or should I bite the bullet and use the lrcat from 2019?
Or start from scratch with a new catalog?
I'm in a lose/lose situation, I'm afraid...
Gary

 

[Johan Elzenga]

You can obviously start with the 2019 backup, to see how useful that still is. If you decide it’s not useful at all, then trash it and start Lightroom Classic with a new catalog.

 

[Califdan]

If you have access through TM to your user data from the old iMac, it may be that your catalog is someplace other than the default "pictures -> Lightroom" folder. Have you searched TM for all ".lrcat" files?

You also don't mention if any of your images are on some external drive. For folks who use external drives for images it is not uncommon for their catalog to also be on the same external drive where their images reside so look there too. Even if your catalog was on the internal HD, it also not uncommon for the "on exit" backups created by LrC to be placed on an external drive.

One other thing, do you have any cloud backups? Whenever backups are discussed it is highly recomended to have at least 2 backup copies of things you care about in addition to the originals. One of those two copies should be kept in some location outside of your local disaster zone. That usually means the cloud. Did you adhere to this advice with a tool like BackBlaze, CrashPlan, Macrium Reflect, Carbon Copy Cloner, or any number of other services? If so, that may save your bacon.

 

[camner]

I came home from a trip at the end of August to discover that my iMac had suffered a hard drive failure, it wouldn't start. I took the Intel iMac and my Time Machine backup drive to my local Mac repair shop, where they replaced the hard drive but found that they couldn't restore from my backup drive because I had opened the drive on a newer M1 iMac which had somehow make the Time Machine backup useless on the iMac it had backed.

Somethings feels a bit off about what they told you at the repair shop. Simply opening the TM backup drive on a newer M1 iMac shouldn’t have been enough to destroy the backup files on the drive, unless when you attached the TM drive to the newer M1 iMac you accepted the Mac’s offer to use the drive as a TM backup drive for the M1 iMac and that process ended up reinitializing the TM backup for the M1 iMac.

It might be helpful if you would post a screenshot of the root of the TM backup drive. It would also be helpful if you would report the earliest and latest dates of backups on that drive.

Here's a screenshot of the root of my Time Machine backup volume. You can see that the earliest backup is from May of 2026. It doesn't show in the screenshot, but if I scroll all the way to the bottom, I can see that the latest backup was an hour ago.

 

[Paul McFarlane]

Have you searched TM for all ".lrcat" files?

This is a sound starting point. If you find some, note the date(s) and sizes.

 

[Resoman]

In my iDrive backup, I found these files dated the day I left town.
If I restore these to my new iMac, will I be in business? Do I restore all of them to the Lightroom folder in the Pictures folder?

 

[bcarlson78248]

I agree that the repair shop analysis seems to be very incomplete/incorrect.

Unless you or Time Machine initialized your old TM backup disk when you connected it to the newer M1 Mac, all your files are still be there.

If you run TM on your new Mac, and connect the old backup disk, TM should allow you to see what is on the backup search it for specific files and restore them.

 

[Califdan]

Wherever you find your catalog folders (TM or iDrive) the two critical file are the ones with file extension ".lrcat" and ".lrcat-data" (in your screen shot the 2nd one is missing). Do not restore the ".lock" file. The others are optional. I'm surprised that I don't see any of your preview folders in your screen shot. They too are optional to restore and due to the incredibly lareg number of individual files in the previews folder, restoring that folder can take quite some time so I usually skip them and let LrC rebuild the previews as needed.

 

[camner]

In my iDrive backup, I found these files dated the day I left town.
If I restore these to my new iMac, will I be in business? Do I restore all of them to the Lightroom folder in the Pictures folder?
View attachment 30384

This is very good news! The fact that you found your .lrcat file from right before your trip should mean that you won't lose previous edits, metadata, etc. You may find when you start up from this old catalog that your image files seem to be "missing." That would depend on whether your images on the new hard drive are in the same place as they were before. If that happens, it's not difficult to reconnect them.

Were you able to restore all of your files that were on your failed drive from either your iDrive backup or from someplace else? If not, it would still be worthwhile to investigate what is on your Time Machine backup to see what can be rescued from there. We can help with that.

 

[clee01l]

Because there is a “.lock” file present, it means that LrC was running when the backup file was created. That “lrcat” file might be in an unstable state and could be compromised or corrupt.


Sent from my iPhone using Tapatalk

 

[Johan Elzenga]

They other two files are not really optional. Restore them too.

 

[Califdan]

They other two files are not really optional. Restore them too.

Care to provide more detail?

The only two items included in the "On Exit" backups are the ".lrcat" and ".lrcat-data" files which alone can be used to to recover a full catalog to a prior point in time. My expeirience is that all the other files can be re-built by LrC from those two critical files with no loss of information. This includes the "sync.lrdata" folder which is rebuilt by comparing the contents of LR with LrC. While there may be some convenience in elapsed time and performance by having one or more of those 2 non-ciritical files I don't consider them as required. Handy, yes -- Required - no. Do you know something different than my understanding?

 

[clee01l]

Care to provide more detail?

The only two items included in the "On Exit" backups are the ".lrcat" and ".lrcat-data" files which alone can be used to to recover a full catalog to a prior point in time. My expeirience is that all the other files can be re-built by LrC from those two critical files with no loss of information. This includes the "sync.lrdata" folder which is rebuilt by comparing the contents of LR with LrC. While there may be some convenience in elapsed time and performance by having one or more of those 2 non-ciritical files I don't consider them as required. Handy, yes -- Required - no. Do you know something different than my understanding?

The Write Ahead Log (wal) and the Shared Memory index (shm) files are consumed by the exit process before the on exit backup takes place. This lrcat file was open at the time the non Lightroom backup was made. (See my earlier post about the risk of data corruption)

 

[Califdan]

Good to know.