Cleaning up empty preview folders

[BobT]

I have preferences set to delete previews after 30 days. Previews are kept in folder Lightroom Catalog Previews.lrdata. In that folder I have 16 folders labelled /0 to /F containing a total of 16,900 folders. Most but not all of these are empty. Are these empty folders kept for a reason? If not, why doesn't LR delete them? It's an onerous task for me to delete them. Can I delete them myself by using file explorer without causing LR issues.

 

[clee01l]

That whole folder structure is maintained by a separate database file called "previews.db" You should not alter the structure of those folders as this could corrupt the database file. A "Folder" is an entry in the file system that takes up no room and merely acts as a place holder to reference files that might be "contained" inside. Actual files are scattered non contiguously in sectors on the disk drive. What used to be called the File Allocation Table (FAT) was a file used by the file system to link all of the sectors that made up a "file". A "Folder" is a part of the file name and sub folders are linked together to make the complete path part of the file name.

 

[BobT]

That whole folder structure is maintained by a separate database file called "previews.db" You should not alter the structure of those folders as this could corrupt the database file. A "Folder" is an entry in the file system that takes up no room and merely acts as a place holder to reference files that might be "contained" inside. Actual files are scattered non contiguously in sectors on the disk drive. What used to be called the File Allocation Table (FAT) was a file used by the file system to link all of the sectors that made up a "file". A "Folder" is a part of the file name and sub folders are linked together to make the complete path part of the file name.

Thanks for that. I understand. The issue I'm having is that I'm attempting to backup the whole LR folder to a cloud drive using SyncBackPro but it's taking hours to read every one of these empty folders in order to set up the backup. Would I be better off deleting all the preview folders entirely, backing up then simply putting up with have to rebuilding new previews as required?

 

[Johan Elzenga]

Thanks for that. I understand. The issue I'm having is that I'm attempting to backup the whole LR folder to a cloud drive using SyncBackPro but it's taking hours to read every one of these empty folders in order to set up the backup. Would I be better off deleting all the preview folders entirely, backing up then simply putting up with have to rebuilding new previews as required?

I wouldn't backup the previews to the cloud at all. Lightroom can rebuild them if needed. I'm in favor of making at least one local backup of your previews folder, so you don't have to rebuild the previews if you don't really need to. Rebuilding previews can take a lot of time, and during that time Lightroom cannot quickly show you a grid of images. For that reason I think that making no backup at all is 'penny wise, pound foolish'. But I would not backup previews to a (costly?) cloud storage.

 

[clee01l]

Johan has covered the essentials of Backing up LR. I have double redundant backups of all of my critical data. I use TimeMachine to back up to a local disk alternating with a TimeCapsule (NAS) disk. I also use CrashPlan in the cloud and to a local disk. CrashPlan took nearly a month to do the initial backup on all of my local disk drives (excluding those dedicated to Backup). After that, it only does incremental backups updating only the files that have changed in the last 15 minutes. CrashPlan also does the same backup to a local disk too. It does this transparently in the background with no manual effort on my part after the initial set up.
If I need to recover a file or a whole disk, I have one of the three local backups (2 Time Machine and 1 CrashPlan) to recover from. If there is a catastrophic event that destroys my home and my home network, I have my CrashPlan in the cloud to recover and restore my critical user data.