Answered

Lightroom Classic Catalog Suddenly Increased in Size

Forum|Forum|7 months ago
December 9, 2025
5 replies
1971 views

Hello,

I have a catalog with around 30k images, for which the .lrcat was stable at around 60Mb in size, and which gets backed up automatically into a Dropbox folder.

A few days ago, the size of the .lrcat file suddendly jumped to around 400Mb. I'm not talking about the previews; just the catalog. When LC exits and backs up, even the compressed zip file that I archive on Dropbox is now >170Mb, which just isn't practical.

Does anyone know of any recent changes that might have caused this? I am discarding 1:1 previews daily.

Any ideas gratefully received,

(Am on MacOS 15.7.2 running LC 15.0.1 with everything on an external SSD drive.)

macOS

Correct answer johnrellis

"I have a catalog with around 30k images, for which the .lrcat was stable at around 60Mb in size... A few days ago, the size of the .lrcat file suddenly jumped to around 400Mb."

Your catalog's .lrcat file is now storing 13 KB per photo (400 MB / 30K photos). That's still on the low side and doesn't indicate abnormal operation.

My two main catalogs use much more: 66 KB per photo (41K photos) and 105 KB per photo (10K photos). But that's still only about 0.3% of the size of the raw photos (typically 21 MB).

One thing that could have triggered your .lrcat increase from 2 KB to 13 KB per photo is if you turned on the option Catalog Settings > Metadata > Automatically Write Changes Into XMP.

B

Bentley B

Known Participant

I have this issue and AI is unusable and can't backup catalog. I looked at the blob files and they are huge compared to the original RAW. So Using the AI edits has greatly inceased the catalog size. Adobe something needs to be done with this large blob file sizes because it makes using AI editing useless unless you have a monster C drive size. For blob file sizes it looks like it can range up to 12 times the size of the original RAW. I don't know if this is the issue but just putting out there because I am computer end user not a computer smarty.

B

Bentley B

Known Participant

To add my blobs, there is 89 files adding up to 19.5 GB which averages to 219.1 MB.

K

kflo7

Participant

I'm amazed at the lack reading comprehension with people here... All these responses telling OP that their catalog backup size is normal for the number of images in his LR Classic catalog is NOT an answer. It's just side stepping the actual question of WHY the backup grew by +650% in just a few days time, with no other changes.

That is extreme and concerning, regardless of library photo count. For anyone that may have many times that photo count in their catalog... their backups will jump up to be in the 10s of GBs. Not normal.

I found this thread because I'm seeing the same issue with my LR Classic catalog backups, and it started in August 2025. Prior to August 2025, my backups were ~160mb, with 27k photo library (close to OP's 30k photos). Then in August, my backups jumped significantly to ~460mb, just like OP's backup. I have optimized and done all other possible optimizations, yet my backups have grown to almost 300% in a short time and stayed at this 300% larger size since August.

I wonder if this could be due to changes made in the LR Classic when version 14.5 was released in August 2025? The list of changes for that update are as follows... "featuring enhanced Generative Remove, improved GPU previews, custom copy-paste settings, new camera/lens support, and bug fixes, along with a subsequent 14.5.1 update for further fixes".

Could it be due to changes in that 14.5 update for "Generative Remove"? My library has quite a few photos using that feature, so it's strikes me as a possiblity. Anyone have insight into this?

K

kflo7

Participant

As a followup to my message above, my suspicions were correct. In LR Classic 14.5 (August 2025), Adobe introduced the "<library name>.lrcat-data" file, which is included in catalog backups. This file is chunky and its addition is the reason for the larger backup sizes from August 2025 onward.

From Google AI overview.... "The .lrcat-data file holds data for AI masks (like Select Sky, People Removal), Generative Remove, and enhanced profile LUTs, essentially storing information for newer, more advanced edits."

K

kflo7

Participant

One correction.... The .lrcat-data file was actually introduced in mid-2024, but seems it was changed significantly in August 2025, leading to the larger backup sizes.

johnrellisCorrect answer

Legend

"I have a catalog with around 30k images, for which the .lrcat was stable at around 60Mb in size... A few days ago, the size of the .lrcat file suddenly jumped to around 400Mb."

Your catalog's .lrcat file is now storing 13 KB per photo (400 MB / 30K photos). That's still on the low side and doesn't indicate abnormal operation.

My two main catalogs use much more: 66 KB per photo (41K photos) and 105 KB per photo (10K photos). But that's still only about 0.3% of the size of the raw photos (typically 21 MB).

One thing that could have triggered your .lrcat increase from 2 KB to 13 KB per photo is if you turned on the option Catalog Settings > Metadata > Automatically Write Changes Into XMP.

JohanElzenga

Community Expert

I agree with @johnrellis . A 400MB catalog for 30K images is tiny. My 210,000 images catalog is 6.13GB. I have a (now) empty catalog that is already 36.6 MB, and another catalog for testing that is 40.8 MB for 1850 images.

-- Johan W. Elzenga

D

Daniel_Wilson8824Author

Thanks to all for your suggestions. I'm a total nube on LRC so am just trying to wrap my head around this. I've disabled writing metadata to XMP as a few suggested; this hasn't made any difference. I've also tried to identify any pictures that had were processed by anything that may have inflated the catalog, as someone else suggested on John Ellis's long thread. I created a filter to check for Denoising or any other AI post-processing. There are zero. I didn't do any of this, except for one (quite large) image where I tried 'Super Resolution' (which one person mentioned might be the culprit). I've already sent this one the printer so de-activated that feature, re-optimised and saved, but the library is still huge.

I accept this may seem relatively small to some of you, but my use of LRC is really simple so I don't want such a big file nor do I need AI touch-up.

Any other suggestions?
Many thanks,

A

AxelMatt

Community Expert

Hello,

I have a catalog with around 30k images, for which the .lrcat was stable at around 60Mb in size, and which gets backed up automatically into a Dropbox folder.

A few days ago, the size of the .lrcat file suddendly jumped to around 400Mb.

...

By @Daniel_Wilson8824

What do you have done in Lightroom in the last few days?

Do you have used the AI Denoising?

My System: Intel i7-8700K - 64GB RAM - NVidia Geforce RTX 3060 - Windows 11 Pro 25H2 -- LR-Classic 15 - Photoshop 27 - Nik Collection 9 - PureRAW 6 - Topaz Photo AI

Ian Lyons

Community Expert

Adding to @AxelMatt comment re Denoise. Super Resolution is also a known culprit for significantly increasing the catalog backup.

A

Aleke

Community Manager

Hi @Daniel_Wilson8824, welcome to the community!
Could you try optimizing your catalog by going to File > Optimize Catalog and see if that helps with the file size?
Thanks a lot!

Alek

*(If you mention me with an @, like @Aleke, I’ll get a notification and can respond faster.)*

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