Inspiring

Question

Why are file lists not identical on two computers reading from same external hard drive?

Forum|Forum|4 months ago
January 9, 2026
5 replies
273 views

I have recently installed LRC on a new computer (Win 11), following the rather minimal Adobe instructions, and now have two laptops using the same version of LRC and the same catalog. My photos are kept on an external hard drive, which both PC's access and use--obviously not at the same time. I have done this a couple of times before without issue, but not this time.

The folder/file list in LRC shows the same folders (and subfolders) on both devices--nothing is missing. BUT, the number of photos is not the same. The total is about 2% less on the newer one, though some folders have more files and some fewer (it's not consistently one way or the other). Also, some carat triangles to the left of the folder names are solid (ok) but some are grayed (or pixilated). The grayed ones do not seem to indicate subfolders. This does not appear to affect the behavior of the contents or display of those folders.

I haven't tried to edit or send any photos from either pc, but I have moved a handful of files without a problem, and I've opened individual photos. I do not get any error messages, such as "file not found," though there do seem to be a lot of those exclamation points about whether to override settings. I generally delete unwanted files from disc and don't just remove them from LR.

I have a screenshot of the folder list on the original computer, so I can compare the names and numbers. I can't compare the actual photos, since Adobe lets me run the program on only one computer at a time. I can't even know for sure whether the edits I have made are the same on both computers.

Can anyone tell me whether there is a way to fix this, hopefully without starting from the beginning again? A more important question is whether the discrepancy has or will extend to newly added photos and ESPECIALLY to edits I make on either device? I had assumed that using the external hard drive and the same catalog would keep the two instances of LRC essentially in sync.

know there are many questions here. They are all related, but I'd certainly appreciate any help with any of them. Thanks.

Gail

'

Windows

J

Jao vdL

Community Expert

Agree with all the other folks. The issue is that the catalog is not the same. Something in the copy process did not work correctly or you are opening the wrong catalog on one computer. The trick to make this (having the same catalog on both machines) work reliably is to put the catalog on the external drive and open it directly from there on both machines instead of copying it every time. This has the advantage of all the support files (the data file, previews, etc.) coming with in a consistent manner and ensures that the catalogs are always identical since it is the same file you are opening.

D

drtonyb

Legend

@MPDAEF

I think some more information is needed here. You wrote:

"I have recently installed LRC on a new computer (Win 11), following the rather minimal Adobe instructions, and now have two laptops using the same version of LRC and the same catalog. My photos are kept on an external hard drive, which both PC's access and use--obviously not at the same time. I have done this a couple of times before without issue, but not this time."

Your photos are stored on an external hard drive and you have two PC latops, that much is clear. When you move from one laptop to the other, you must be removing the external drive from one and plugging it into the other. Ok so far. Now you catalog which needs to be shared between the two laptops.

"The only thing I can think of is that the plain .lrcat file didn't show up in the usual place, and I had to do a search for it. It was there, however, and revealed by a search. There were several .lrcat-data files, but none without the -data part of the extension was visible until I did a search. The same is now true of the new install. I thought that might be a change in the newest version, but maybe not."

The catalog is the catalog_name.lrcat file; here I'm using catalog_name to represent your catalog's name. It should be stored in the same folder as other support folders, catalog_name.lrcat-data, catalog_name Previews.lrdata, catalog_name Helper.lrdata and possibly some others. It is good practice to have your catalog in a folder named catalog_name. There should not be several .lrcat-data folders without associated .lrcat files, so this does not make much sense. Nothing in any LrC updates would cause this either.

What is the name of your catalog and more importantly, where is your catalog stored?

M

MPDAEFAuthor

Inspiring

It is in Libraries/Pictures/Lightroom folder, and it is New
Catalog-2-2-v13-3-3-oct25
with various extensions (helper, previews, etc.)
I don't usually rename catalogs of new versions but stay with the Adobe
names.

The .lrcat-data files do seem to proliferate like rabbits. (I know that
some files, like the lock file, come and go depending.) I don't delete
them, since I cannot tell them apart. That may be a big part of the
problem. What I transfered was just the catalog_name.lrcat -- with no
further extension. That did seem to transfer everything, but obviously not
quite right. I'd love to clean up that folder, but I would obviously want
to do it safely.

Gail

JohanElzenga

Community Expert

The .lrcat-data is part of your catalog. It contains all kinds of AI stuff, such as AI-generated masks, generated remove, denoise and super resolution data. You should copy that too, but because it is relatively new, it may not be mentioned in outdated information about moving Lightroom to another computer.

If you want to use the same catalog on two computers, then copying catalogs all the time is a recipe for troubles, however. Sooner or later you'll make a mistake, resulting in data loss. The question is not if that will happen, only when it will happen. The only way to do this properly is to copy the catalog folder (not just the catalog file) to the external hard drive as well, and run Lightroom on both computers with the catalog on the external drive, so you really use one and the same catalog on both computers.

-- Johan W. Elzenga

JohanElzenga

Community Expert

I have recently installed LRC on a new computer (Win 11), following the rather minimal Adobe instructions, and now have two laptops using the same version of LRC and the same catalog. My photos are kept on an external hard drive, which both PC's access and use--obviously not at the same time. I have done this a couple of times before without issue, but not this time.

OK, so you share the same images on both computers. But where is that catalog located? If it is located on your internal drive (the default place) on both computers, then you started off with the same catalog, but as soon as you made some edits, imported some new images, or deleted some old images, then the catalogs were no longer the same. What you do on one computer, will not be recorded in the catalog on the other computer. They do not remain synced, just because they have the same origin. That would explain everything you mention...

-- Johan W. Elzenga

M

MPDAEFAuthor

Inspiring

Unfortunately, that does not explain why the discrepancies in the number of
files in various folders were there from the beginning--before I made a
single change to anything at all! The copied/transferred catalog is
clearly NOT the same as the original, even though I made no changes at all
to either. I have to assume that something in the transfer process caused
this, although I did follow the instructions.

The only thing I can think of is that the plain .lrcat file didn't show up
in the usual place, and I had to do a search for it. It was there,
however, and revealed by a search. There were several .lrcat-data files,
but none without the -data part of the extension was visible until I did a
search. The same is now true of the new install. I thought that might be a
change in the newest version, but maybe not.

In the future, I'll need a way to keep the two catalogs synced, but that
isn't the immediate issue. At the moment, I can't figure out how to start
them off in sync--or how to solve a more complex problem if there is one.

Thanks for your help.

Gail

dj_paige

Legend

The folder/file list in LRC shows the same folders (and subfolders) on both devices--nothing is missing. BUT, the number of photos is not the same. The total is about 2% less on the newer one, though some folders have more files and some fewer (it's not consistently one way or the other). Also, some carat triangles to the left of the folder names are solid (ok) but some are grayed (or pixilated). The grayed ones do not seem to indicate subfolders. This does not appear to affect the behavior of the contents or display of those folders.

Show us screen captures. Please use the Insert Photos icon to include your screen captures in your reply. Do not attach files.

And I would avoid synchronizing folders at this time, until we have a good understanding of what is happening on your computer. Synchronize folders could make the problem worse.

M

MPDAEFAuthor

Inspiring

[image: image.png]
Here are two screenshots. This is top part of folder list on second (new)
computer. Same piece of original folder list is below. I hope this
works. I don't know how to do it another way. (I replied to another
response detailing the problem finding an .lrcat file without a -data
extension, but I did find it--or the transfer wouldn't have worked, of
course.)

[image: image.png]
If you need this done differently--or if you need more--please explain how
I can get you what you need.
Thank you. G

D

drtonyb

Legend

@MPDAEF

Screen shots did not come through.

E

ExUSA

Legend

If there are differences, you can't be using the same catalog file. Have you tried synchronizing your folders that have a discrepancy? That would update the catalog you have open.

M

MPDAEFAuthor

Inspiring

Well, that's the problem, of course--the instructions are to copy the
.lrcat file onto an external drive and then copy it into the LR folder on
new computer--that is, following the same path to the same place. That
shouldn't change anything inside the file or it wouldn't be a copy--and it
likely wouldn't work.

(There are other pieces of this thread being posted.)