Sounds like, after you edited the photos and exported a copy, you removed the photos from LR and re-imported them at a later time. Is that what happened?

Have you opened a backup catalog by mistake?  Do a search for your catalogs (search for .LRCAT).  Opening a backup catalog would explain what you are seeing.

John

John G. Blair Studio

Occidental, California

Sorry, typo: a catalog is ending on .lrcat.

A catalog backup is just the same file as your working catalog at the time the backup has been created

So if you have continued afterwards with another catalog, then with the backup version again, you will miss some edits.

How often to create a backup?

You specify this in the catalog preferences.

For an enthusiast photographer who earns his living by some other job than photography, once a week may be enough, depending on how many shoots you create.

For a professional at least once a day or every time LR is closed would be more advisable.

You can always set it to "when LR next exits", which will do that, but leave your normal schedule untouched.

Advisable whenever you did big imports, edit sessions or changes.

Or before you feel inclined to do some reorganisation.

Save the backup to a different drive, as your main drive may fail... Dito for your photos themselves.

Cornelia

Yes, "Delta" means the difference between two catalogs. It is usually used for increments, if one version has the same as the other but then still some more.

Determine new images: you could look by capture date.

I just tested what happens if you import from another catalog, that is already included in your current catalog:

LR checks for duplicates. In the options offered for "Replace" you can choose

• to replace Nothing: that means the current catalog wins and the overlap is ignored
• to replace metadata and develop settings only
• to replace metadata and develop settings and negative files: that means the other catalog wins, the overlap is taken from that one

If you are unsecure if you might have worked in both catalogs for develop, you can tick the  box "Preserve old settings as a virtual copy": that means LR will know 2 develop versions afterwards, which you can manually compare and maybe cleanse any time later (or never).

So it will just take longer if you "Import from Another catalog" without first looking for the delta, but will give you the same result.

How many images do you have in your catalog?

With 100'000 or more it might take a while, for example a night.

Cornelia