LR 5.6 - does LR always save edits in catalogue, even if "write XMP to sidecar" is enabled?

[Guermantes]

Hi!

I put my questions first, and the reason I ask them after that:

1. Does LR always save all editing data and "everything that is needed" in the lrcat-catalogue, irrespective of whether I have set it to write sidecar XMPs?
2. Or is there some kind of weird interplay going on, with lightroom only getting the full edit-history by combining the XMP-data with catalogue-saved data from the last few months when it could not write to the XMPs any more?
3. Can I safely delete all my sidecar XMPs, now that I can't update them any longer? Is there a procedure to follow, to make sure that the catalogue has integrated all data from the XMPs before I delete them?
4. I am also curious as to why I was never notified by LR that the XMPs were not updated for old files, or even created for new files. (this one you can't answer without continuing reading below)

I am one of those who's writing sidecar XMPs. This was all fine when I had 4 HDDs in my desktop. Then I built a NAS-server and moved all my source raw files and jpegs to the NAS. Wanting to move the catalogue to the NAS as well, I discovered that LR can't use a catalogue on a network location (I am using Windows 7, by the way). So I moved it back to the local HDD. At the time, it did not strike me that this meant that my sidecar XMPs could be compromised.

All was fine for months and I have been editing, importing new files, deleting bad ones, etc. Only today did I notice that all my sidecar XMPs had unaltered timestamps since the first time several months ago when I moved them to the NAS. This has me confused. Lightroom clearly knows of all the edits I have done since, but the XMPs have not been updated.

I presume this means that LR is unable to write the XMP to a network location. (I don't understand why though, since it is able to write backups of the catalogue to a network location.)

[cmgap]

Not sure what you mean by your sidecar files could be compromised...

If you have Write changes to XMP files Lr will write changes to the sidecar file of the image that it is tied to. So if Lr sees your original in folder 'A' and the sidecar file is in the same folder 'A' that is where the changes will be written to. Select an image > right click and Show in Finder... is the XMP file in the same folder?

Lr will write the changes to the sidecar file on the NAS if that is where the original is.

The catalog can't be on the NAS but the images and XMPs can and changes will be recorded.

[Guermantes]

Hello!

Yes, "compromised" was not a good word choice. What I meant was if something had broken that I was not aware of.

cmgap  wrote

Lr will write the changes to the sidecar file on the NAS if that is where the original is.

The catalog can't be on the NAS but the images and XMPs can and changes will be recorded.

I made some further testing and I find that the above is only true if:

• I import new files (I was wrong on that point previously), or
• I delete the existing XMP (alongside original) on the NAS, or
• I forcible "Save XMP to file" and then confrim overwrite settings on disk.

After that new edits will be written to the NAS XMPs.

If I just open LR and start editing a file, LR will not update (or will silently fail to update) the XMP file.

So it would seem the transfer of the RAW files + XMPs to the NAS broke something, even though I went through the procedure of "locating originals from new location" when I first started LR after having moved the files.

Question remains, how come LR is able to remeber my edits if neither of the three conditions above are true?

[Ian Lyons · Accepted solution]

Guermantes  wrote

Question remains, how come LR is able to remeber my edits if neither of the three conditions above are true?

Lightroom stores everything you do to the catalog (lrcat file). This is the primary location for everything (other than previews) you do in Lightroom. Saving to XMP (sidecar) is a secondary option, and cannot be used as an alternative to the catalog.

[Hal P Anderson]

Lightroom always saves your edits in the catalogue. Always, whether you write changes to XMP or not.

Hal

[Guermantes]

Thank you, Hal !

Ian got the correct answer tick simply because he was a minute earlier.

[Guermantes]

Then it is true, that at any moment, as long as my catalogue is not corrupt, I can safely delete XMP sidecar files without losing years of editing?

[Hal P Anderson]

Yes.

[cmgap]

No - do not delete your XMP sidecar files without converting the images to DNG unless you will never use other applications like Bridge. Please review this before you do: XMP Sidecar Files « Julieanne Kost's Blog