Lightroom Classic 8: Previews catalog problem

  • 1
  • Problem
  • Updated 4 days ago
  • (Edited)
I have an Imac Pro 32 gb of memory and a 1tb ssd internal hard drive.  I have a 16tb external thunderbolt hard drive.  I updated to LR9, but was having lots of problems...called support and was escalated to a senior tech.  He reverted me to LR8.4.1.  Running good, but I had to recreate my previews catalog.  So far I have created 1:1 previews of 100,000 of my photos.  the catalog is 1.4tb.  It took 4 days to create these previews.  When it was finished I closed LR to have it do a backup.  The first part went well but it bogged down when it started to optimize the previews catalog.  After 8 hours I called support and was told to be patient as it was a large catalog.  At 24 hours I got intermittent messages that LR was not responding.  At 30 hours I got a message that my system resources were at a critical stage and I needed to exit LR.  I called support this morning  and was told that they would have a senior tech call me this week.  Seriously.  
I can run LR, but am not sure that the 1:1 previews are accurate because I had to interrupt the optimization.  
Does anyone have any suggestions or thoughts on what my next step should be?
Thanks for any help.
Photo of Bill Wood

Bill Wood

  • 1 Post
  • 0 Reply Likes

Posted 5 days ago

  • 1
Photo of Johan Elzenga

Johan Elzenga, Champion

  • 2412 Posts
  • 1005 Reply Likes
There is no such thing as a ‘previews catalog’. The previews are stored in a folder inside the catalog folder. On Windows this is a normal folder, on Mac it is a so-called package. A package is a folder that looks like a file and can be double clicked in the Finder.

Lightroom can and will rebuild any preview that it needs. There is no reason for you to build thousands of 1:1 previews. Let Lightroom build them if and when it needs them. A 1:1 preview is only needed when you zoom into 1:1 to check things like sharpness and noise. It is not needed for day to day work with your images. Lightroom will keep the previews up to date.
Photo of Cletus Lee

Cletus Lee

  • 107 Posts
  • 33 Reply Likes
When LR Classic v9 converted your older catalog file, it renamed your previews folder to " {new catalog name} Previews.lrdata".  just rename that to " {old catalog name} Previews.lrdata". And make sure it is in the same folder as your old 8.4.1 catalog file. 
Photo of Edmund Gall

Edmund Gall

  • 98 Posts
  • 30 Reply Likes
One other fundamental question to consider: Why do you need to regenerate 1:1 previews for all 100,000 photos? Correct me if I'm mistaken, but you only really need a 1:1 preview when you're editing photos: so, if you've finished editing them, why keep the 1:1 previews (or regenerate them) and waste all that disk space?..
Photo of Johan Elzenga

Johan Elzenga, Champion

  • 2409 Posts
  • 1002 Reply Likes
No, you don't even need them when you are editing, because the Develop module uses its own (different) previews. Like I already said: you only need 1:1 previews if you are checking things like sharpness and noise at 100% view (in the Library module). Generating 100,000 1:1 previews is a waste of time and drive space.