Lightroom Classic 10 catalog size

I am using a Mac with the latest Mac OS. I happened to have a "testing catalog" that has 54 photos in it, and not many edits. I simply noted the sizes and then opened with LR V10.

Before v10, the .lrct file size was 7.7 MB. and after the upgrade to V10 the .lrct file size was 7.4 MB.

Before v10, the Helper.lrdata file size was 131 KB. and after the upgrade to V10 the Helper.lrdata file size was 268 KB

Before v10, the Previews.lrdata file size was 133.6 MB. after the upgrade to V10 the Previews.lrdata file size was 133.6 MB.

So, no it would not seem to be a MAC bug.

My suggestion would be to move the newly updated lightroom files to another external drive or flash drive is possible (basically these 3 files when the application is closed: 

Lighrroom Catalog-v10 Helper.lrdata

Lighrroom Catalog-v10 Previews.lrdata

Lighrroom Catalog-v10 .lrcat

Then with Lightroom V-10 installed, open the previous version of your catalog , i.e. the file labeled Lightroom Catalog.lrcat, and update it along with its helperlrdata and it s previews.lr data.

THen check to compare the file sizes of. your old catalog files and the newest v-10 files.

If these look more in line with what they used to be, I would think there was some sort of hiccup during the upgrade.

And Unless you have done any work to some photos in the interim, the new v-10 files should be the same as the previously updated v-10 files, so you could delete the ones that look unusally large.

Win 10, LrC V10 and V9.4

1. In the new blank catalog I created in V10, I imported 50 images. The new catalog file size is 2.9MB

2. In LrC V9.4, I created a new blank catalog and imported the same 50 images. The V9.4 .lrcat file referencing 50 images is 2.9MB. 

3. Upgraded the 2.9MB .lrcat in V10. The V10 .lrcat is 2.8MB.

Good luck figuring that out.

You're probably dealing with the icc profile infection bug. It is a really strange bug that has plagued users for a while where custom icc profiles used in the print dialog get copied into the catalog files 100's of times, even into newly created catalogs. Here is a thread on it: https://community.adobe.com/t5/lightroom-classic/lightroom-classic-cc-8-0-large-sized-backups-and-lrcat-file/td-p/10289146?page=1

After reading most of your posts and looking at the screen shot you included I have to suspect an OS FUBAR Seeing and Report the actual File size of the upgraded LrC V10 catalog.

But then you say a New Catalog with 60 images is the same 900+ MBs.

My LrC V9 catalog is 275MBs. After conversion to LrC V10 it is 274MB and that is with 17,000+ images in it and my LrC Test V10 Cat is 3.69MBs.

You might have to uninstall and reinstall LrC V10 and Delete the new V10 catalog and when you reinstall LrC V10 let it upgrade you catalogs again.

On my Windows 10 20H2, a brand new catalog is lees than 2MB. I imported a dozen photos, its now 3MB. So I would think this is a Mac issue.

Definitely something weird going on.

What happens if you open the old catalog in v10 and it does the data migration again?

Mac OS 10.14.6

I have both LR9.4 and 10 running. 10 is not useable because of the slowness but the upgraded catalog is the same as what I am running on 9.4. Your mention of catalog size got me checking my catalog. Both catalogs stayed at 1.3GB but the Previews file shows a huge difference. 9.4 previews is 21.23GB while the 10 previews is 52.5GB. I wonder if this is part of the problem make 10 so slow it is not usable.

That doesen't sound right. 

I'm just leaving for the day, but when I have the chance, I will add 50 images to the new V10 catalog and post the results. I will also try converting a small V9.4 catalog with 50 images and convert that to V10.

My system is Win 10 Pro.

Please post your Operating System and version. What is the number of photos in your catalog? How many catalogs are you using?

While that is a huge change, that is not a huge catalog. I have 180,000 photos referenced in my catalog and the file is 2.16GB. The .lrcat file size did not change with the upgrade to LrC V10. I'm not sure how a catalog could be as small as 8MB. I created a new blank catalog and the .lrcat file is 1.57MB. It will grow quickly as image files are imported.