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All Lightroom previews disappeared!

E

Eyecake

New Member
Joined
Apr 9, 2023
Messages
11
Lightroom Version Number
15.0.1
Operating System
  1. macOS 26 Tahoe
Good morning and Happy ?new Year.
I was editing a photo in the develop module when a popup occurred roughly saying LRC has encountered a problem with the Preview Cache File and it had to close.
When I reopened LRC everything thing was blank. In the library module all was blank except for file name and EXIF data
Clicking the development setting button in lower right corner open-end the image in the Develop module with the adjustments applied so images and edits are the I just can't see them.
There are about 30,000 images in this Catalog from a recent trip of a Lifetime safari to Kenya with about half the images with preliminary edits.
I am happy the pictures are there. I think they are all backed up to the cloud but if it is only a link to the previews that would save a lot of time.
This forum has been a great help before.
Thanks for looking
 
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The previews cache is the 'catalogname previews.lrdata' file in your catalog folder. Lightroom can rebuild it if it has such a problem, so move it out of that folder (or trash it) and start Lightroom again. Initially you will not see any thumbnails, but then they should appear one by one.
 
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Eyecake said:
I think they are all backed up to the cloud but if it is only a link to the previews that would save a lot of time.
Click to expand...

No, your images are not backed up to the cloud by Lightroom! Make a local backup.
 
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Johan Elzenga said:
The previews cache is the 'catalogname previews.lrdata' file in your catalog folder. Lightroom can rebuild it if it has such a problem, so move it out of that folder (or trash it) and start Lightroom again. Initially you will not see any thumbnails, but then they should appear one by one.
Click to expand...
Thank you for the Advice Johan. My thumbnails are all back although the first time after I deleted the Preview file no images appeared but I then optomised the catalog and restarted and thumbnails started to appear.. Success!
I am using a Mac Studio M1Pro and a fairly fast SSD drive for the Library view when I double click on a small thumbnail I get a pixellated version and a small pause while it builds a bigger preview. It then seems to build a bigger preview on about 7 photos either side of viewed one which display immediately.
This safari library and photos are on a Crucial X9 drive 1Tb formatted in EX FAT. Probably should have reformatted Mac Disk system before using but forgot.The transfer speed is 1050 MB/s while my main library and photos are on NVME 4Tb with a ThunderBolt enclosure with probably 5 times the transfer speed so maybe the slow response is the slower disks fault.
The Histogram window just says Original Photo. "I cannot see a command to make previews and in the preferences the Preview size is set to medium.
I hope I am making sense.
 
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Select all photos, then choose 'Library - Previews - Build Standard-sized Previews'. Before you do this, go to the Catalog Settings. There you can specify the size of the standard-sized previews. Don't set this too small, because if you have too small standard sized previews, then Lightroom will have to build a bigger one when you view the photo in loupe view. Either use 'Auto', or use 2880 pixels (depending on the size of your screen).
 
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Both Develop and Library previews can be deleted with no ill effect. I do that regularly. As stated they start to rebuild as soon as you view your files. Your edits are safe in both the Lightroom Catalogue - lrcat and Lightroom Catalogue - lrcat-data folders.
 
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We're still not getting back to the original issue which casued the problem - something happened to the Previews folder making it unusable. Normally this does not happen. The OP did not mention anything about a power outage, a system crash, someone tripping over a drive cable or any such thing. Just they were happily editing in LrC and it went wonky. The most likely causes of such an out of the blue event are 1) Disk drive going bad, 2) Connection (cable) to the drive with the catalog going bad, and 3) The folder containing the catalog is being synced to some cloud service like OneDrive or iCloud+ or Google Drive (the worst being OneDrive).

These 3 possible causes should be checked out by the OP - Especially #3 as if such a service is involved it's the most likely culprit.
 
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Califdan said:
We're still not getting back to the original issue which casued the problem - something happened to the Previews folder making it unusable. Normally this does not happen. The OP did not mention anything about a power outage, a system crash, someone tripping over a drive cable or any such thing. Just they were happily editing in LrC and it went wonky. The most likely causes of such an out of the blue event are 1) Disk drive going bad, 2) Connection (cable) to the drive with the catalog going bad, and 3) The folder containing the catalog is being synced to some cloud service like OneDrive or iCloud+ or Google Drive (the worst being OneDrive).

These 3 possible causes should be checked out by the OP - Especially #3 as if such a service is involved it's the most likely culprit.
Click to expand...
Hello Dan
Thank you for reply. you could be on to something about One Drive. The last day I used Lightroom I exported it about 300 JPEGs to my OneDrive account which is supplied for my photographic college course and I use at times to move files I'm working out I'm at home to have them available to include in college projects. I did notice this morning I message also saying files syncing but I have not used this particular Safari catalogue to sync with life from in the cloud like I've done for my main catalogue so what was sinking at the JPEG is not finished exploring or the other day when I closed the computer or did I think them instead of export JPEG I'm really not sure but it was definitely thinking going on that I didn't understand.

Thank you very much guys for reading these posts and helping less season users like me understand and get better at using Lightroom which I've used for a very long time but it just keeps getting bigger and better and more facilities and with my college course I have to find new uses for it.
 
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The main thing is to assure that the folder containing the catalog is not involved with something like OneDrive. Having the actual image file folders synced with OneDrive and the like is usually not a problem.
 
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