Hi John,
Would you please clarify the precise version of Lightroom you are using? The best place to get that information is using System Info... from the help menu. Please copy and paste the first 5 lines from the System info window. That will give us the exact version and os release that you are running.
I would be cautious about trying anything else until this situation is sorted out. What ever you try do now try to re-import that is almost always one of the least useful actions to take in situations like yours.
Generally changes in behavior such as you describe are a result of some other seemingly unrelated activity on your computer, software update etc.. Do you recall anything like this that happened recently?
By replying with your system info that will bump your question back to the top so that others will look again.
-louie
Louis,
Thanks for the reply. Here is the system info........
Lightroom Classic version: 9.3 [ 202005281810-476e492c ]
License: Creative Cloud
Language setting: en-US
Operating system: Mac OS 10
Version: 10.13.6 [17G13035]
As you can see, this iMac is still running High Sierra. Until I am able to relocate an old scanner to another less-used iMac, I am unable to upgrade the OS.
This problem began with the catalog not opening, and its repair not functioning. This occurred two days after a normal shutdown. I restored from that backup catalog file.
That process seemed to work just fine, except for the syncing of mobile files, which seemed to stall with around 100 remaining (of about 15,000). So, I did an option-click on the preferences window and rebuilt the sync data.
That process produced one file in the 'all sync errors', and then stalled again. The file looked OK, and I tried to remove and replace it from the synced collection, which did not help. Ultimately, I removed it completely, and the sync process continued, now not stalling, but slowing towards the end, and producing a lot of uploads. Eventually, it completed, and everything appears normal again.
During the sync process, and apparently, until I resolved the single file issue, the program was very unstable, crashing whenever I navigated folders. It now seems stable.
Throughout this episode, I did not import or edit any images except for the following. I did take a couple of photos with my iPhone, which would normally sync up to the desktop. They would not sync up until I rebuilt the sync data.
What is troubling about this entire event, is the apparent damage that it did to the rest of my computer. This computer had three external HD's attached, one of which contains the image files and the catalog files. The other two are backups, one a Chronosync system backup, the other Time Machine.
All three external drives were changed to 'Read Only' when LR crashed. 'Read Only' in the root folder only, so data continued to write to the LR catalog. Several times, I manually changed the permissions back, but each time LR crashed, it got switched back to 'Read Only'. Time Machine saw the root folder as 'Read Only', and would not function, nor would it allow me to manually correct it. The disk needed to be erased and re-written. Luckily, TM is only a small part of my backup strategy.
Looking forward, I will probably scale back my use of the 'mobile syncing'. It has not proved to be very useful with the limitations of the mobile app and web app.
Again, thanks for the help.
John