Hi,
Today I found out that for what it seems, Lightroom Classic CC (7.3) does NOT seem to update the default Smart Preview file (Lightroom Master Catalog Smart Previews.lrdata).
As you can see on te below screenshot (apologies for the Dutch names):
All Catalog related files appear to be "touched" when opening Lightroom.
Just before I took this screenshot, I deleted several Smart Previews and then regenerated them.
From what it appears, only the "Lightroom Master Catalog Previews.lrdata" is modified.
Another confusing issue is that, according to Lightroom, the size of my Smart Preview Collection is about 49GB but none of the files have a size that matches that (with some overhead differences).
For additional info, here's a screenshot of some of the other Catalog settings:
I do have several other Catalogs. The most recent one of them does not appear to have this issue (although I just cleared that one out completely), but the other one also seems to be affected by this issue:
With all this in the back of my head I get the impression that Lightroom is storing my Smart Previews somewhere else, but searching my entire hard-disk does not reveal anything that looks like a Smart Previews collection file.
Or is Lightroom modifying the Smart Previews collection file without tampering with the "File Modification Timestamp"?
FYI, I'm running Lightroom Classic CC 7.3 on a MacBook Pro running MacOS High Sierra 10.13.4.
Any ideas on how to further investigate this?
Regards,
Rob.
Het bericht is bewerkt door: Rob van Eerd I re-added the screenshots, this time from files instead of the clipboard.
1 Correct answer
The smart previews are in that folder. Windows allows you show the date the folder was CREATED, or the date the folder was MODIFIED, and normally these will not be the same. I believe that your column heading in the screen capture Berwerkingsdatum is the date the folder was CREATED, and not particularly relevant here.
6
Replies
Thanks!
You pointed me in the right direction!
Although "Lightroom Master Catalog Smart Previews.lrdata" appears to be a Folder on Windows, on Mac it just appears as one of those "Items" which look like a file (see first screenshot) but underneath, it's a Folder, See the screenshot from the Finder below:
Watch the "d" at the beginning of the line.
What still is a little confusing though is that the "Lightroom Master Catalog Previews.lrdata" DOES change its modification timestamp. But my guess is this one not only contains additional sub-folders, but also files and when these might be recreated, the master folder's timestamp is modified.
So I guess my confusion is solved 
Regards,
Rob.
Hi,
Yes, I do agree that your solution works on all platforms.
Revisiting your original post, I came to the conclusion that you made a wrong assumption in translating "Bewerkingsdatum". Dat in fact is the MODIFICATION timestamp.
So for completeness, I do have the other ones as well, except not shown:
- Bewerkingsdatum = Modification
- Aanmaakdatum = Create
- Openingsdatum = Open
- Toevoegingsdatum = Added
In that light, it does make a difference between Mac and Windows. Not specifically because of where the Smart Previews are stored, but how that item is shown.
Items like the "Lightroom Catalog Smart Previews.lrdata" are shown as a "Folder" on Windows, but as some kind of a regular file on MacOS. So be it, this lesson will stay with me, so thanks for that
To figure out where the non-adjustment of the MODIFICATION timestamp comes from, one has to dig into how Folders and Files are treated when being used. I figured it out but I won't go into the details here as that comes down to Operating System Architecture details and is off-topic here.
However, if one does want to know a little more, look at the explanation I gave in my initial response to your valid solution.
For me, this case is now closed.
Thanks for the info provided! 
Regards,
Rob.
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