Sharing a Lightroom Catalog across multiple computers

Note: This article was updated (26/2/2015) to reflect some changes to how BTSync works :)

So you want to have a single Adobe Lightroom catalog that you can use on multiple computers and have them all show the same pictures and edits? But you don’t want to manually copy files around or carry hard drives in your bag.

OK so this has taken me bloody ages to get right but its not that complicated if you have some basic computer skills and don’t mind getting your hands a little dirty. A while back I figured out how I could do this with Apple’s Aperture over in this article but since then I have moved to using Lightroom because… well they had nicer presets at the time :P I don’t have any love of either product so its good to know how you can bend them to do what you want.

The basic problem with Lightroom catalogs is that they don’t like being on a network drive and not everyone is happy lugging a portable hard drive around between computers with their catalog’s or RAW files on. This is the usual hack to get around it. It is a pain and you run the risk of losing your archive unless you have a decent backup strategy.

The way I have my systems setup is like this:

  • I have a central NAS connected to my network. All my computers can map to this in the same way.
  • All my computers are Mac. This is only a issue if you are sharing a Lightroom catalog between a Windows and Mac machine as the drive mapping on a Mac is something like “/Volumes/Graphics/Images” whereas a Windows box will be “G:/Images/”
  • The individual machines don’t all use a single Lightroom Catalog file but rather each has a copy of the catalog that is synchronised over the local network or Internet.

Drive with photos in one location

So how do I synchronise the catalogs automatically?

This is where BitTorrent Sync  (BTSync from now on) comes into the mix.
BTSync works in the same kind of was as DropBox with the advantage of being completely controlled by only you and with no size limitation. You can also use a piece of software called SyncThing which is basically the same as BTSync but with Open Source roots.

What I have done is set up a folder that BTSync will synchronise onto my other machines. When I modify a catalog on my desktop, the changes will be replicated to my laptop and visa versa. A large Lightroom catalog can be anywhere from 1Gb or larger. BTSync should only send the parts of the file that have changed over the net so even with a slow bandwidth, you will be able to keep a catalog in sync over the internet. This does depend on what parts of the file are changed and sometimes it will just copy the entire file. Having all your machines you want to keep in sync on the same network is a best practice.
Lightroom does generate a couple of files and folders that you do not want to replicate between machines.
These are the following:

  • ‘CatalogName Previews.lrdata’ – This folder contains all the temporary previews for thumbnails and 1:1 previews lightroom uses to run smoothly.
  • ‘CatalogName Smart Previews.lrdata’ – This folder contains smart previews that Lightroom generates if you want to edit on a laptop without the RAW files being online. This is brilliant for laptop warriors on the road.
  • ‘CatalogName.lrcat.lock’ – This file is a lock Lightroom creates so other processes wont try modify and potentially corrupt the catalog.
  • ‘CatalogName.lrcat-journal’ – A temporary store before final info is written to the catalog.

So how do we exclude these files and folders? This is where a bit of digging under the surface comes in but before we do that lets start of with getting BTSync working.

You should alway make a backup of your catalog before attempting any of this. I have been running it without any problems for about 2 months but computers are shit and will break. I have my main catalog on a computer running Time Machine backups and create a manual backup every couple of days just in case.

  1. Download BitTorrent Sync (BTSync) from their website and install it on all the machines you are going to keep in sync
  2. On the machine with your original catalog or catalogs; create a BTSync share by either running through the setup wizard or in the main interface clicking on the ‘+ Add Folder ‘button.
    BitTorrent Sync Main Screen
  3. Click the ‘Generate’ button. This will create a shared secret key that you will need to copy down and not let anyone else see. If somebody else copied down this Shared secret, they will have access to your Lightroom catalogs.
    (If you are worried about somebody guessing your Shared Secret, don’t worry about it too much. Steve Gibson gives a good description of its working and how difficult it is to brute force here on episode 402 but there are enough combinations of letters and numbers in that little box to address each individual atom in the Universe with its own key. )
    BitTorrent Sync Create new share
  4. Now comes the secret sauce. BTSync will look for a hidden folder called “.sync”
    Inside this is a file called IgnoreList. There is a good article here on what all the options are for this file.Eg:

    In this file we define all the folders and files we don’t want sent over the network.  Open this up in notepad if you are on Windows or pop open a terminal and navigate to the folder you are sharing eg ‘cd Pictures/Lightroom-Catalogs’ and then open it in a text editor eg

    cd .sync
    nano IgnoreList’

    (Note: with the new version of BTSync, this is now named IgnoreList wheras previously this was just a file in the root folder called “.SyncIgnore”) This will create the file if it does not already exist.

  5. Fill in the following lines:

    /AO2-2012 Previews.lrdata/*
    AO2-2012 Previews.lrdata.!sync
    /AO2-2012 Smart Previews.lrdata/*

    Obviously my Lightroom catalog is called ‘AO2-2012.lrcat’ so replace your catalog name or names with your own.

  6. Create the same file on your other machines in the root folder of the share you setup on them. You can also just copy this file to the other machines.

Thats it! Restart BTSync on all the machines and after a few minutes your catalog will be replicated to all the machines and kept up to date. A archive is automatically created in ‘.sync\Archive’ folder if your catalog is smaller than 1Gb so remember that if you start running out of space for no reason. You can modify BTSync’s settings to lower this number.

One of the best advantages to this setup is that I can now take my entire library of near 100 000 images on the road with me. When I want to work on a project in Lightroom on the road, I can just select the folder and generate Smart Previews for that project. I can do basic edits on the images (nothing involving external plugins or Photoshop)  and hve all the changes synced back to my other machines.

Another great advantage is you can setup a lot of NAS devices with BTSync now to automatically sync a version on itself for added redundancy and to have a catalog with your RAW files.

Hope this helps someone. Let me know if there are any questions.



  1. This looks a really useful approach and I’ve got it running fine. I’ve used the syncignore file as you’ve suggested but I’m not clear what its actually doing with the previews. Does syncignore stop ordinary and smart previews being copied between computers?

    Could you detail the bit about going on the road a bit more. Are you taking your whole image library with you on an external drive? It sounds like you just generate smart previews and take those – do you generate them on the laptop that you travel with? Once you have edited the smart previews on the road how do these changes replicate back to other computers that you sync with if smart previews aren’t synced? Is the edit information held in the cat file and not dependant on the smart preview in any way?

    Finally what happens if you load images onto the travel laptop while on the road – whats your approach to that?

    Thanks for a really good tip. I’ve been using the cloud drive sync for this and its a pain with speed issues on my connection. BTsync is much better

    29/07/14 at 14:13 · Reply
    • Hi Warwick.

      You have pretty much hit it on the head.
      I have my main library on a desktop iMac at home and my original RAW files on a NAS server.
      When I go on the road, I open my laptop and make sure everything is synced up.
      I then open Lightroom and tell it to generate Smart Previews of the project I am working on. This creates lower resolution Lossy RAW file previews on the laptop. These files are not synced.
      I can then hit the road and work on these images away from my original RAW images that are stored on the NAS server.
      When I get back onto the internet or my home network, the main catalog is synchronised back to my desktop iMac.
      All changes are stored on the Lightroom Catalog. As this is the only real file that is synchronised between the machines, all changes become visible on all the machines that are set to synchronise at once.
      I don’t let it copy the Preview files or the Smart preview files between machines as they typically end up being many gigabytes in size and take bloody ages to sync up.
      My laptop is only used to to work with on the road and I will prepare for that by letting it generate the preview files or Smart Previews of what I know I am going to work on.

      Its really just to make it quick to sync up.

      Hope that helps :)

      01/08/14 at 17:32 · Reply
  2. Very interesting approach.

    Just wondering, for this to work with Smart Previews on the road, do I first need my images to be on some type of NAS? If they’re not, what will happen? I’d imagine that Smart Previews cannot be generated if the computer can’t find the originals?



    02/10/14 at 6:33 · Reply
    • Hi Paul.

      Yes you are correct. If Lightroom cant find the files, it wont be able to use them to generate the smaller compact Smart Previews.
      The reason I put them on a NAS is so that I can have the files accessible from a variety of machines and not taking up space on them.
      The only thing synchronising between machines is the catalog itself.

      24/10/14 at 12:15 · Reply
  3. Hi Anton,

    I stumbled upon this article searching for how to use LR with a NAS as photo storage, because I have a (Windows) desktop computer and a MacBook Pro, both with LR5, and recently bought a NAS so I’d have a shared data base and not some photos here and some there.
    While I was mainly interested in how to teach LR to use a network storage with LR (and learnt how to use previews and smart previews), your approach is also sharing the catalog(s), which made me wonder: Should I do that too?

    Now I am just a hobby photographer (so far I have about 18k photos), and also I am not a LR expert, so could you elaborate a bit on why you chose to do this? I mean, couldn’t you as well just right click the top folder and hit synchronize and let it search for newly added images and metadata updates? What advantages does it have going the (officially unsupported) way of sharing the catalog over that?

    I realize it might be a time consuming process if you have a LOT of photos in the catalog, as you certainly have, being a photographer, but then again you seem to seem to have multiple catalogs even per year. Are there other reasons? I’m having LR convert my raws to DNG during camera import and I chose to have LR store changes into/with the files, so that shouldn’t be an issue.


    16/10/14 at 7:13 · Reply
    • Hi Jay

      You are in a difficult situation where you run two different environments (Windows and Mac).
      They unfortunately use different ways to refer to network storage. Windows maps a drive letter to a share (EG: F:\ShareName\Images or \\ServerName\ShareName\Images) whereas the Mac uses a local mount point (EG: \Media\ServerName\Share\Images)

      It becomes a challenge as you would constantly have to use Lightroom’s fix missing media option to point your catalog to your NAS share each time you jump from your Mac to your PC.

      I cant think of a easy to use solution for you. Sorry.
      Even replicating a local folder with all your images stored on your drive would still lead to the same problem of having to point Lightroom at the changing path between Mac and PC.

      As for the way I use my Lightroom catalogs:
      For each job I do I create a stand alone LR catalog that lives on a portable hard drive. I back that up separately each day.
      Once I’m finished editing those photos and they are ready for archiving, I import them into my main LR catalog which is BT synchronised across my machines. I then delete the temporary catalog on the portable drive.
      This keeps my workflow lean and quick but I still have access to all my files if I need them.

      Thats just me though :)

      Hope that helps.

      24/10/14 at 12:10 · Reply
  4. 1. Wonder what happens if you are on the road with your catalog and smart previews while someone back at the imac edits a job on that catalog. Does the sync system merge the changes?

    2. I have a mac pro and am adding another mac pro to the office for an assistant to come in and filter photography. Is it possible/advisable to have the images stored on my computer and share out my system to her without actually implementing a standalone NAS?

    23/10/14 at 10:24 · Reply
    • Hey Sean.
      Because the system has a central Database (DB) file that all the edits are stored in, any changes to smart previews are also replicated to the DB.
      If you take your catalog on the road and do edits without being connected to the net, the home system would not know of those changes. If someone edited files (even completely different ones) the changes are written to the DB file and its timestamp would be updated.
      When your laptop finally connects to the net again, the Bit Sydc would see that your home machine has the last file changed and would replicate it to you laptop. Any changes on your laptop would be lost.
      This would happen even if you have your catalog preferences set to write changes to XMP files.

      24/10/14 at 11:59 · Reply
  5. Hi, set things up with the new beta (1.4) and I guess it’s working based on history reports. However, I

    a) expected keywords to be updated, i.e. have LR on 2 PCs and one is “further along” in kwing than the other

    b) ditto on OTHER PC for Title, Headline, & Caption

    No joy. Any ideas or am I expecting something that can’t be done short of catalog copying?

    Thanks, and appreciate your hard work in discovering and exploring this technique.


    17/11/14 at 11:07 · Reply
    • Hey I.G
      As far as I know, keywords are kept in a separate location on your PC.
      Mac is something like /Users/UserName/Library/Application Support/Adobe/Lightroom/Keyword Sets
      PC would be something like C:\Home\Username\Application Data\Adobe\Lightroom\Keyword Sets (Totally made that up so don’t quote me on it :P)

      You would need to setup another BT Sync folder for each of these. It would probably be a good thing to do it for only the items you want Synced to minimise bandwidth and the potential for something going wrong.

      There are a bunch of different items in here that can be synced in a similar way but I haven’t had a play with it yet. This would be a great place to sync your presets and adjustment brushes as they are all stored in that folder.

      17/11/14 at 13:31 · Reply
  6. “Computers are shit and will break…”
    Truer words have never been spoken – thanks for the article.

    22/11/14 at 14:35 · Reply
  7. Hi Anton,
    You seem very well educated on LR, and I have been searching to no avail for a solution to a problem I’ve been having.
    I will try to explain, and hopefully you can help.
    I work for a photographer that creates a new LR catalog for every single wedding he shoots. My job is to process the best of the photos, and flag certain ones.

    He creates smart previews, then copies the entire catalog along with any of its additional folders to a drive and gives it to me to open on my Mac for processing. We both use macs, and have the same version of LR.
    When I’m done, I give him the files back. At first, I was returning everything he gave me for data, files and all.
    We noticed that when he now tries to export the images at full resolution, somehow they are getting resized. His original file size of 4000×6000 is changed to 1000×2000 and he needs the largest size.

    We are CERTAIN nothing is checked in the export dialog box that would do this. Is there something else we need to consider? Something in how or what we share for data?
    More recently, I have returned only the lrcat file to him rather than all the preview files. Still unable to figure out why this is happening.

    Neither of us understand LR to the point we can troubleshoot this, and this is the first time I have ever worked with multiple catalogs, or same catalog on two different computers.
    So in summary, our main problem: File resizing on export when we create jpgs of the raw edited file.
    Do you have any guidance you can offer?
    Thanks in advance.

    23/11/14 at 4:25 · Reply
    • Hi Victoria

      Thats a bit of a strange one.
      Smart previews are a fantastic way to edit your images on the go while the RAW images are on a disconnected drive. Changes are propagated back to the RAW images (assuming they are in .DNG format) once you connect the drive back.

      The first thing that comes to mind for your issue is that when you bring the catalog onto the Photographers computer, his machine may not know where the original RAW files are. You can export images with Smart previews but they are at a lower resolution. I think this is what is happening in your instance.
      Try re-connect the Original RAW files by switching to the Library module, right clicking on the folder and selection “Update Folder location”
      Select an image and verify it is the original RAW file by looking at the labels under the Histogram. There are a couple of icons that represent if it is a Smart Preview or Original file or combination.
      This article is a good intro to it by Adobe.

      A second thing to try would be to delete the Smart Previews by switching to the Library or Develop module, click Library > Previews > Discard Smart Previews.

      Let me know how you go :)

      26/11/14 at 10:45 · Reply
  8. I have followed your instructions above to the letter but BTSync is still copying over the lock files, and I can only assume that is also copying over the smart previews at the same time?

    Any idea what I could have done wrong?

    21/12/14 at 3:21 · Reply
    • Hi Paul

      Not sure what it could be but try checking that the file names are in the correct case.
      MacOS is case sensitive and windows is not. In saying that I believe BTSync sees everything as case sensitive.
      One thing to also try is to quit BTSync on both machines, delete all the preview files and then start them up again. Then run Lightroom on your Laptop and re-generate the preview or smart preview files. Then quit Lightroom and see if they appear on the other machine. That will at least tell you if the files are being copied over or not.
      There appear to have been some changes to BTSync recently that has changed its behavior. I’ll try figure it out soon and post an update.

      28/12/14 at 12:30 · Reply
  9. Hi Anton

    Thanks for this guide. This is very useful as I plan to use LR5 on my MBP (primary) and macmini (secondary) while having my images stored on a Synology NAS.

    I am however inexperienced on steps 4 and 5 so I need a bit more hand holding so really appreciate. I managed to open the terminal in utilities and went into text editor.

    Question is whether is I need to copy the entire box wordings above or just these few lines.

    /AO2-2012 Previews.lrdata/*
    AO2-2012 Previews.lrdata.!sync
    /AO2-2012 Smart Previews.lrdata/*

    Also after I enter in text do I just close the terminal window as it does not appears i can do a SAVE to the file. Last but not least I cannot see the file (.syncIgnore) in lightroom root folder so not sure how to copy to my other machine.


    23/12/14 at 1:47 · Reply
    • Hey Dexter

      One thing to know on the Mac is that any files that start with a period are not shown in the Finder window.
      The are hidden files or folders (its a weird throwback from UNIX)
      the Mac also has a security system that relies on elevating privileges.
      You will have your standard account you are logged in with but you can elevate its privileges to an admin in order to do certain taska. This is what the “Sudo” command does.
      You use it by typing “sudo” then the command you want to run as an admin
      EG: “sudo nano .syncignore”

      You were probably unable to save some of the files you edited because the system sees them as files only an admin can edit.
      As for the editing of the file and what wordings you need to copy:
      You should only need to copy few lines.
      Just remember to edit them to match your catalog name :)

      As as side note: after the last update to BTSync, I am now having trouble syncing my libraries.
      I’ll have a crack at figuring it out soon and post an update.

      28/12/14 at 12:21 · Reply
  10. Hi Anton

    Thanks. By the way the new the new version of bt sync uses IgnoreList instead of syncignore. I got it to work finally.

    But one thing I need to be careful is when LR catalogs are syncing I should close LR on all the macs. I can’t get the catalog of mbp to macmini initially and in fact mbp catalog was over written.. Does BT Sync allows me to designate which one is master?


    01/01/15 at 13:30 · Reply
    • Hey Dexter.
      Ive updated the article (finally) to reflect the changes they made and that you pointed out. Hopefully more people will find it useful now :) Interestingly, BTSync seemed to automatically rename the old file to the new one. It just started one day again on my systems :P

      26/02/15 at 17:04 · Reply
  11. Thanks for sharing this! My issue is that I create a new catalog for every single job (wedding, portrait, etc.) & don’t work off of one single Lightroom catalog. Wondering if you have any idea of a possible solution if I’m constantly creating new catalogs without having to go through these steps each & every time. Thanks!

    17/01/15 at 3:08 · Reply
    • Hey Austin
      You have me a bit stumped on that one. Im not sure you can do anything other than edit the files each time.
      The way I work is that I create a separate catalog for each job that I work with on an external drive. Once Im done editing, I import that small catalog into my main catalog where all my photos are.
      Thats pretty much it.
      Everyone has a different workflow :)

      26/02/15 at 17:19 · Reply
  12. Hello,

    Is it essential to have a NAS server to get this to work? Can I save my catalog drive on an external drive on my original master PC? Then my secondary pc/laptop needs to have the catalog saved on the C: drive correct?

    I’m having problems with the program not working because of the network limitations/error.

    Thanks for your help.

    21/01/15 at 4:09 · Reply
    • Hi Matt
      Nope its not essential to have a NAS but you will just need to make sure that your drive mappings to your images are the same on both machines. If you have an external drive with your images on (say the g: drive) You will need to share this on your main machine and have a network drive mapped to G: on your 2nd machine that points to the external drive on the main machine.

      26/02/15 at 17:07 · Reply
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