How to use PhotoLab on multiple Apple Computers

Currently I have PhotoLab 5 on my 2018 Mac Mini desktop, and also on my 2015 MacBook Pro laptop. When I’m home I use the Mini, but when I’m traveling it’s the MacBook Pro.

(After buying PhotoLab 5 I installed my previous version of PhotoLab 4 on a different (backup) iMac computer, and if I ever needed to, which I don’t expect, I still have a license for PhotoLab 3.)

My question is how to set up a single storage area for my images. Right now I have most of my images on my Mac Mini, but from all my trips locally and overseas, those photos are on the MacBook Pro.

Specifically, right now I want to edit the photos I took last week, and I prefer working on the larger calibrated display on my Mini.

The best solution I can come. up with is to buy yet another external drive, and move ALL my photos to it. That way I can connect it to any of my computers, and edit any of the images.

Unless I’m missing something, this should work fine for my desktop and laptop, but I suspect my backup computer, with PhotoLab 4 installed, might not open image with “.dop” files configured for PhotoLab 5. I doubt I would ever really need to do this though.

Plan “B” which is easier, is to simply move or copy all my images from my MacBook Pro to my iMac.

Plan “C” could be to put all my images on a fast network drive that I could access from any of my computers.

Before I try to set this up, am I missing something? Will things work as I expect?
Will PhotoLab 4 open files created by PhotoLab 5 ?
Will PhotoLab 3 open files created by PhotoLab 5 ?

The topic of using PhotoLab on more than one computer has been covered already, albeit for Windows mostly.

A few things must be taken into account.

  • Location of photo files and sidecars
  • Location of the database files
  • How to back up all of the above
  • Interoperability or lack thereof

I propose you read the thread mentioned above. It might give you a foundation on which you can build on.

Thanks - will check this out now. I do keep my “image files” including the dop file together, in folders, and do this the same way on my computers. I don’t know anything about “database files”. Hopefully what I find at your link will explain.

I have two “issues” to resolve, how to get my desktop and laptop computers to play nice with PhotoLab, and what to do about images that I need to edit in DarkTable because PhotoLab does not support them. No urgency on any of this, but I do need to find the best way forward. Again, thank you @platypus

If at all possible, I would recommend you get yourself a large external SSD for storing your photos in a shared location rather than keep on copying them from one computer to another, but that is up to you.

One thing that is very useful is to be able to quickly and easily delete you PL5 database files before opening PL5 on a shared folder, or simply a folder that contains files previously edited on another computer. This will ensure that only the DOP files will be read and you will not end up with loads of meaningless virtual copies from PL trying to cope with both the present DOP files and what it thinks it should have in its database.

The easiest way to get to the database files is to create a Smart Folder or Saved Search in Finder…

Start by opening a Finder window and navigating to ~/Library/DxO PhotoLab v5/…

You can easily see the database files and now what you want to do is to create a Smart Folder to make it easy to get back there in one click.

Start byt searching for file names that contain “dopdata”

This then filters out all the others and enables the Save button…

When the Save dialog appears, you can save the search top wherever suits you (in this example I chose my desktop) and you can also check the box at the bottom top add it to your Finder sidebar…

This then makes your sidebar look something like this, except mine contains other searches for when I am beta testing.

Then all you have to do is to select all and delete…

Capture d’écran 2021-12-15 à 16.41.45

If I have totally blown the brain cells, let me know and I will explain it better.


Yes, you have, and what’s left of my brain cells have given up on this idea completely. I’ll just use both computers, to access whatever files I have stored on each.

I’d rather use my remaining brain cells to improve my skills with PL5. :slight_smile:
Everyone else, please ignore my last two posts.
DxO, please make this easy and effortless. Eventually. :slight_smile:

Working with PhotoLab on more than one computer can a) be done or b) get you an incredible mess.
Let’s see how we can do a) without the b)…starting with your saying that you use PL for customising only.

Work consistently (Hub / Spoke model)

  • Keep all your images in one structure, using something like the example shown below
    Photos > YYYY > YYYY-MM-DD Occasion > YYYY-MM-DD Occasion Details

  • Make one computer the “HUB”, e.g. the one with the big, calibrated screen,
    while the other computer will be the “SPOKE”

  • While traveling, copy new images, on SPOKE, to the appropriate place,
    create branches (YYYY-MM-DD Occasion > YYYY-MM-DD Occasion Details) if necessary

  • While traveling, only work new images, LEAVE ALL OTHER IMAGES ALONE

  • When back home, copy new branches, on HUB, to the appropriate place

Spraying new images all over SPOKE and customising (on SPOKE) images in older branches will inevitably lead to a mess that will take a lot of time to sort out and that might also produce some loss in effort you put in your images.

Work consistently (Peer mode)
If you really want two (or more) computers to work as peers, things are getting complicated, as you’ll have to synchronise the computers on a regular basis. PhotoLab has nothing to support that yet.
Forget peer mode! Note: I can say this because that’s what I tried with my iMac (HUB) and MacBook Air (Spoke) computers. I use Spoke for testing mostly and for those rare cases when I really want to have it with me. Still, Spoke will be deleted regularly, which makes it less of a peer. Don’t try to use peer mode, unless you’re comfortable with having disparate collections in several places (like mixing knives, spoons, forks, pans and dishes in the same drawer)

Yikes! That’s still complicated :crazy_face:

But you are absolutely right. Most of this mess is caused by being obliged to use the PL database as well as DOP files and, when you import files with DOPs from one computer to another, PL tries to reconcile the database and the DOPs and ends up creating total confusion, usually accompanied by a plethora of virtual copies for those “versions” it deems irreconcilable.

Please DxO, this needs addressing as using more than one computer is becoming more and more common.

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Interestingly, no one has opened a feature request for that stuff yet…

I use a NAS and 2 pc. I synchronize the pc’s with the NAS. This way I’ve all the images on both pc’s and the NAS. Not the perfect solution, but it works for me.
I’m on Windows.


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PhotoLab Sync Feature Request: Vote!

I’m still new to DxO’s structures. My Capture One “catalogs” (databases) are on an external TB3 SSD. They grow while my internal SSD doesn’t and I cannot exchange it. I’m currently reading where the DxO database is stored as I also want it to be somewhere else than in the application support folder. Like @platypus I also use a MacBook Air with a 1TB external SSD when abroad and so far I just copied the folders to my RAID after arriving home. That contains DOP and maybe XMP files (if I like to add GPS or keywords). So far that worked and until I know better I didn’t try to merge databases.

Only copying the image folders can get you issues like the following: Add a setting, which will then disappear when you open the image on the other computer. Such effects can be caused by how and when PL reads or writes sidecar files. New files will be read first (imo), but older, reworked files can get messed up through overwriting new settings with old ones from the database.

Automatic sync of .dop and .xmp sidecars can make sense, but there is no way (yet) to tell PhotoLab when to to which action. We’d need settings (or popup questions) like “overwrite old settings/keywords/metadata” or “preserve old settings/keywords/metadata” that let us choose which source of information is the one we currently trust.

One way to control the above is, to disable automatic r/w of sidecar files and manage the actions ourselves.

This may or may not be helpful to others. I think it will allow me to copy folders from my laptop onto my desktop in an organized way. I’ve opened the “Finder” tool on my desktop computer, and it shows only my photos since December 2021 currently on my desktop.

Way at the left I have the Apple folder PICTURES. In my first column to the right of PICTURES I created a folder _2021 December (for work that I will be creating this month).

Next column shows all the folders inside of the _2021 December folder. The folder name is created by PhotoMechanic when I ingest new photos, with folder names in the format year-month-day-short description (as was suggested in this forum).

I clicked on the last entry in that column, and the folder to the right of that column shows the contents of that folder I clicked on, in which PhotoMechanic automatically renames the files as file-number-year-month-day-filetype.

Here’s a screen capture:

My latest plan is to use PhotoMechanic on all my computers to “ingest” photos from my memory cards, re-naming folders and files in the above formats.

Moving ahead, to the topic of this discussion, I hope I can COPY everything I captured last week on my MacBook Pro, which is currently stored in a _2021 December folder on that computer, and PASTE it into the _2021 December folder on my desktop.

As for Using PhotoLab with two computers, I’ll wait until DxO comes up with a proper solution.

In January next year, I’ll be creating a folder named _2022 January, and that’s where photos taken in January 2022 will go.

(I think my computer will show things alphabetically, meaning February will be above January, but I don’t see that as a major problem.)

I rely only on XMP and DOP files and set PL to automatically write to these files. I can then copy my photos along with these sidecar files to a central location when returning from an excursion. I occasionally delete my database to keep things tidy and speedy.

If I need to manage more than what is in the sidecar files I will use my DAM (Photo Mechanic Plus) on a subset of my photos.

I did buy the Photo Mechanic Plus, intending to eventually use it for DAM, but I need to learn how to set that up. Eventually I’ll get around to it.

I have never deleted my PhotoLab to delete its database deliberately, but I think between PL3 and PL4 the installation program did this, if I remember correctly. How often should I do it, and for that matter, how do I tell PL5 to do it safely?

Thanks - my “central location” will be either on the main drive of my Mac Mini, or perhaps on an external high speed drive. In that case, I’ll be asking here about what type of drive would be best to buy.

@mikemyers I am a Windows 10 user not a Mac user but I believe both versions use an SQLite database and I have written at great length (sorry big posts appear to be a habit of mine) about the issues of the wrong DOP meeting the right (or wrong) database entry Unwanted virtual copies - #86 by BHAYT.

If a database is oblivious to a particular Photo in a particular directory/folder it will absorb/ingest/import the DOP automatically based upon the ‘Preferences’ for handling sidecars (DOPs) or when manually directed to ‘Import’ the sidecar (if you manually import you will always wind up with a Virtual Copy - the photo before the import counts as the [M]aster and the import becomes copy [1]). If it has never seen that photo before then all should be O.K…

If the database has “seen” that photo before, i.e there is a database entry for that exact photo in that exact directory (currently PL does not check and start matching up the same photo filename regardless of the directory as some other products do! at least on a PC) then a check swings into place that will determine the fate of the attached DOP, but PL5 will protect the sanctity of both the database entry and the incoming DOP at all costs.

The field is the Uuid just behind ‘ShouldProcess’ as shown below

there will be a similar Uuid for all copies held in the DOP. I haven’t run a test were one of the photos [M] or [VC] matches the database and the other(s) doesn’t (don’t) but certainly a mismatch between the [M] Uuid and the database is going to start the creation of Virtual Copies!

So the only way to import successfully, regardless of what media you use or whether you access the original photo across a LAN (I have done that with some success but only by dividing the exports between two systems and then …) once a Uuid is allocated that will not/does not match the system you are going to import it into there will be Virtual Copies; you can escape this fate by ensuring that there is no corresponding entry in the database you are importing into, i.e. by throwing away the database so there won’t be a problem!!!

If you doubt the above the test is simple;

  1. Edit a photo in PL5
  2. Open the DOP in a text editor and change the last digit in the Uuid I identified above, i.e. in my example change the 3 to a 0 and then save the DOP file.
  3. In my tests PL5 has picked up the change instantly and I have a shining new Virtual Copy to play with (whether I wanted one of not)!!

I have “moaned” about the fact that the VCs cannot be promoted to [M] status etc., there is much that DxO could do to help manage the fall-out from this situation but that is in the future perhaps. Things might be simpler of more complex on a Mac but the above comes from many tests that I have run on a PC.

Hi @mikemyers, if you look in the preferences you will find a setting where you can specify a location for your database. Note down this location then close PL. Go to that location in Finder and delete the files you see there. There should be no other files other than the database files (2 or 3 files?). Now you can start PL and a new clean database will be created automatically.

I delete my database about once a month but it is a personal choice as to how often. The more directories and photos you view in PL the more data is stored in the database.

PMP is quite complex program but once you get used to it you will find it very useful. The great thing about it is it can have multiple databases and you have complete control over what is stored in the databases as well as how they are used (read/write, read-only or not used). You can search all databases too or just selected databases.

Hope this helps.

The database files can be found here:

Instead of “macadmin” you’ll see your user account name :wink:

Note that deleting the database will obliterate everything you have done and not saved to sidecar files.

Hi Bryan, I agree with your assessment and can confirm that the database is indeed SQLite.

I think the aim of DxO is to store all PL specific details on DOP files and the database. All other standards-based data in XMP files and the database. Currently this is not quite the case as some data like keywords and ratings are still stored on DOP files and I suspect is often ignored. This has caused confusion on these forums at times but I hope DxO will fix this soon.

I made the suggestion that DOP files should ONLY contain PL-specific data and other common data stored in XMP files (and database). This should make data management and synchronisation simpler and more understandable.

My desktop computer has never seen the photos I took last week on my trip. After a long talk with a fellow at Apple Tech Support, I took a high speed USB drive, plugged it into my laptop, then copied the folders I created last week. Then I copied them to my desktop computer, where PL5 worked perfectly with them.

This isn’t what I was asking for, but it does solve my immediate need - get my recent photos off the MacBook Pro, and onto my desktop.

All my Mac computers have the updated OS, and no issues.