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Delete Previews and Rebuild in LrC 10.

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Denis de Gannes

DdeGannes
Premium Classic Member
Joined
Oct 18, 2007
Messages
1,102
Location
Republic of Trinidad & Tobago
Lightroom Experience
Advanced
Lightroom Version
Classic
Lightroom Version Number
LrC. 10.1.1
Operating System
  1. macOS 11 Big Sur
I am a user since 2007 when LrC was released. Basically I normally use the basic options when using the application. I have been having problems with LrC for the past few months on my iMac 2015 5K 27” which are related to the GPU, which gets recognised by my computer automatlcally, however I experience problems with the application which will be relieved when the GPU is turned off. I am not confident that this will be corrected by an update from Adobe or Apple. I have started deleted the previews and commencedvrebuilding standard previews.
My folder structure is by year and I rebuilt back to 2016 so I have to go back to 2001, it will take some time and it it has already taken over 8 hours.
This is the first time I am doing this procedure I have a couple of questions.
1. It's taking 3.5 seconds per file to complete the process, almost all raw camera files?
2. There is consistent syncing to Creative Cloud taking place is that a normal necessity when building previous of synced images?
 
Hi Denis

Unfortunately rebuilding Previews won't help with the GPU performance issue - not sure what you expected this to do. But yes, with a lot of images building previews can take some time!
Building them shouldn't invoke any sync; did something else change at the same time? Like Write to Metadata? That would do it.
 
Hi Denis

Unfortunately rebuilding Previews won't help with the GPU performance issue - not sure what you expected this to do. But yes, with a lot of images building previews can take some time!
Building them shouldn't invoke any sync; did something else change at the same time? Like Write to Metadata? That would do it.
I do not have the option, Automatically write to xmp, selected. No xmp or DNG for me.
 
Then something has made Lightroom think there's been a change to the photos, but building Previews isn't the cause (it doesn't affect the actual photo itself at all).
 
Then something has made Lightroom think there's been a change to the photos, but building Previews isn't the cause (it doesn't affect the actual photo itself at all).
I am proceeding with the rebuild and now 2014 is in progress will eventually get to 2001. Have not seen sync taking place as often as yesterday.
Did a test which indicate it takes approximately 3.5 seconds for each preview. The files are 98% raw camera files.
 
What size previews are you building? I know you said "Standard" in the first post, but what size and quality is that set to in your Catalog Settings?

3.5 seconds average seems very slow for standard previews, although of course preview generation will be affected by the number and type of edits that are applied (especially local adjustments). But for comparison, the last time I ran some timing tests on my late 2013 MacBookPro running Mojave it averaged 0.47secs per file on my "edited" test set (but local adjustments weren't applied), that was generating 2880px previews. If you're using a 4 or 5k monitor, the preview size is likely to be larger, but even so 3.5 seconds average sounds a lot. Are you doing other things in Lightroom while that activity is goiung on, as that could impact the speed?
 
I know it is a little late to be making this suggestion, but why do you need every preview? My recommendation (had you asked) would be to only select the recent images and rebuild for those. If you later in the normal workflow select a group of ancient images, Lightroom will rebuild these on the fly. There will be a small pause while Lightroom rebuilds previews for this select group of ancient images But you will never need to wait hours for Lightroom to build ALL of your previews at once.


Sent from my iPad using Tapatalk
 
Ok, So I am back after nine hours since my last post and Jim's reply earlier today. I have been back and forth to my computer since then chugging along with the building the new preview trying to speed up the process. and my TV box following the "Donald Impeachment saga".
I have come up with the theory of why I keep generating intermittent sync activity. Earlier today I had paused the sync to the Creative Cloud and proceeded to create the new previews for several years. About an hour ago I reactivated the sync option, and sync activity started again.
Jim's advice kept bugging me and think I understand the reason for the activity.
Cletus your post has convinced me that my thoughts were probably correct. Ok some additional info.

1.In late 2014 I purchased a new Olympus camera E-M1 and I was pleased with the support and profiles that were supplied by Adobe so I have never created user camera profiles for the new camera. This is something I had done for several of my earlier cameras.
2. In mid 2015 I switched to my iMac system from a Win system that I used since using Lightroom in 2007. Since I was not using the older cameras I never carried the user profiles to the new system. If I ever revisited older images I would get a warning that the profile was missing and I would reedit with the new updated process version and profiles.
3. Whenever I upgrade Lightroom I just upgrade the catalog and I have never had to delete my Preview file totally and rebuild. This is the first time.
4. I have only synced image files that are in specific collections to the adobe cloud.
5. All my work in on my Makintosh HD which is not a SSD and maybe that also affect the speed on the rendering of previews. That is what I experience when importing files from my SD to the computer.
I am attaching some screen capturers that might help.
Screenshot 2021-01-13 at 7.07.26 PM.png
Screenshot 2021-01-13 at 7.14.21 PM.png
Screenshot 2021-01-13 at 7.16.06 PM.png
Screenshot 2021-01-13 at 7.19.12 PM.png
 
Wow! I am having a couple of issues with my iMac with macOS Big Sur and LrC !0.x which are GPU related. I am now seeing this post in another unrelated thread, Is it possible this is what is slowing down the rebuild of preview files on my system.
This is not a bug it is a Big P**A!!
Screenshot 2021-01-13 at 9.41.13 PM.png
 
Adobe releases a major upgrade to LrC v10.0 on October 31, 2020, and Apple responds with a major upgrade to macOS v 11.0 on Nov 12, 2020, and users struggling with multiple bugs.
Adobe releases an update to v 10.1 and Apple updates to v 11.1, Adobe releases v 10.1.1 and still no relief from most of the bugs
 
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