Returning Images to DxO after Lightroom

I think you may run into trouble in trying to use PhotoLab on two different machines, pointing to the same set of images (on your SSD) … because PL insists on creating a unique database on each machine (it cannot be convinced to share one - because the database format used does not support multi-users).

The unfortunate result is that you will see spurious Virtual Copies of each image, as PL tries to deal with what it sees as duplicate sets of correction details for each image.

See here for more discussion on this.

John M

On a sidenote, when using Lightroom as the central hub, is it neccessary to have a Photolab database as long as the .dop files are kept along the original raw files?

No it is never essential to use the database for saving adjustments unless you use projects or the persistent history, or if you want to use the search facility.

However, in the kind of situation where you are using more than one computer to access the same external drive, you would need to delete the database, that PL needs for caching purposes whilst running, either before or after every use on each machine.

I thought edit history wasn’t persistent? I asked a while a go and it was “nope”

Hi John

Thank you very much for the information. I kind of guessed that would be the case, hence me trying to use Lightroom for the cataloguing (which you can use between machines), after batch processing through DxO. I have used the same machine when trying to batch process through DxO, export to Lightroom, then bring back into DxO.

I had imagined though that the ****_DxO.dng files retained the DxO information once imported into Lightroom, but have since discovered this is not the case of course (Thanks Joanna).

I will certainly follow the link for more information and really appreciate the response,

Kind regards


Quite correct, and I think this is what I will have to do. It means though that I will have duplicates of all my files if I batch process the whole lot each time. I guess it makes more sense to select only those that I really want to use DxO on. A shame, because after the batch processing in DxO, I had a much better idea of what I wanted to keep and process further than I would have had from the original raw files.

Thanks again


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up til now, that’s for the MAC people only

That’s what I do. I don’t shoot for clients (no weddings or corporate) nor do I sports and such, so I don’t come homes with hundreds of files to batch process in no time. I cull, select, catalog and process in LR and only send to PL5/FP/VP when needed. Most of my keepers are done that way.

You can try and put your PL database on your external SSD too. This should solve any problems with shared database and .dop files.

Yes, that should work. I don’t use PL on multiple PCs - but I don’t want/need/value ability to use keywords or projects - and I prefer to rely on the sidecar/.dop files associated with each image, rather than hope that the database never becomes corrupted or disassociated from the image files it represents … so, I run PL via a “wrapper” that first deletes the database file(s) before invoking PL … and, of course, I have preferences set so that sidecar/.dop files are automatically ingested and updated.

Here’s the basic .CMD file that I use, for anyone interested:

Yes, Mac retains history across sessions - but the Win version does not … Again, tho, I don’t value that (whilst acknowledging that others do !) … All details of corrections made to an image are retained in the sidecar/.dop file (tho, not the minute detail of every step taken to reach that result).

I assumed that would/should work too, Keith … but “someone” (I can’t find the reference now) tried that and found that PL insists on creating a database that’s unique to its host PC - even if they’re stored in the same place … tho, I cannot confirm that as I don’t run multiple PCs.

John M

DPL (win) seems to provide the possibility, but with DPL (mac), things get more complicated. One needs to a) copy the database to the new location and b) edit preferences files accordingly. And while this worked when I tried it a few days ago, I’d not want to rely on such a workaround though.

The database is just a simple SQLite database and as long as there is nothing in the database that requires a specific computer to access it, then there should be no reason it can’t be shared on an external SSD as long as only one computer acesses it at a time.


As far as I know, you can set the location of the database in DPL’s Windows version.

DPL for macOS does not provide such a facility and there is no guarantee that the modified location will work in any case. If there is just one place in the app with a hardwired DB address, you’ll get an issue -and at the least welcome moment probably.

Yes, Windows does allow you to specify the database location. I did not know that Mac does not have that feature :crazy_face:

Added it here (even though the thread was originally meant for DPL4)

Thanks @platypus :grinning::+1:t2:

Standard path in Windows

Before with PL3 and 4, I had changed it to my ‘scratch disk’, which is also M2.NVMe – so no difference.

Regarding sharing one PL database between multiple systems;

I found it:

I don’t have multiple systems, so cannot confirm this … but it’s conceivable that PL behaves like this to provide protection against potential for attempted simultaneous access on non-multi-user SQLite db.

John M

Interesting! Thanks @John-M

I have two laptops and an externally SSD so will test sometime.

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I have tested using an external SSD containing photos AND the database. Both laptops are windows but one is Windows 10 and the other is Windows 11.

Here is what I did:

  1. I setup a test folder and the database on one laptop with Windows 10 and visited all the directories in my test folder.
  2. Disconnected the SSD and connected to my other laptop running Windows 11.
  3. Started PL5 and set the preferences to the database on the SSD and restarted PL5
  4. Everything worked with the database on the SSD and I could search keywords and browse photos without issues

I think this shows that you can share a database between multiple machines without issues.