Lightroom Desktop: freezes when pasting settings
I use a Mavic drone to shoot hyperlapses, usually in excess of 600 photos. Once imported into LR, I will adjust the develop settings for one photo, then copy and paste those adjustments to the entire batch of photos. This evening, Lightroom pasted the settings to two photos, then...stopped. It just sat there, doing nothing, with the progress bar in the corner frozen. I can scroll through my images and click on them but the Paste command ceased. I wound up killing the Lightroom task and reopening, and the problem didn't go away. I rebooted, same problem. Uninstalled, ran the CC cleanup tool, and reinstalled. Still freezes. I tried copying and pasting the settings to ONE photo, and it froze. After killing the task again and trying ONE photo, it worked, so I tried a selection of 60, and the Paste command froze immediately. Usually a batch of over 600 photos only takes a few minutes.
Until this most recent update, I have not had this problem.
Help > System Info is below.
Lightroom version: 4.0 X64 [ 20201007-0818-b2c04b4 ] (Oct 7 2020)
NGL Version: 18.104.22.168
WF Version: 3.0.1 e2e396b
Operating system: Windows 10
OS Version: 10.0 
Application architecture: x64
System architecture: x64
Computer model: System manufacturer System Product Name / Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz
Logical processor count: 8
Processor speed: 4.2 GHz
Built-in memory: 32699.4 MB
Real memory available to Lightroom: 32699.4 MB
Real memory used by Lightroom: 2199.9 MB (6.7%)
Virtual memory used by Lightroom: 2682.0 MB
Memory cache size: 7882.5 MB
Internal Camera Raw version: 13.0 [ 610 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 21MB / 16349MB (0%)
Camera Raw real memory: 22MB / 32699MB (0%)
System DPI setting: 96 DPI (high DPI mode)
Desktop composition enabled: Yes
Displays: 1) 1920x1080, 2) 3840x2160
Input types: Multitouch: No, Integrated touch: No, Integrated pen: No, External touch: No, External pen: No, Keyboard: No
Graphics Processor Info: DirectX: NVIDIA GeForce RTX 2080 (22.214.171.12471) - 8 GB
Graphics Processor Detail: loaded: Yes, supported: Yes, compute: Yes, init: I4_GPU3, hard: success, soft: success, wl: Yes, bl: No
OS Media Capability: true
Application Folder: C:\Program Files\Adobe\Adobe Lightroom CC
Settings Folder: C:\Users\Mark\AppData\Roaming\Adobe\Lightroom CC
Library Folder: C:\Users\Mark\AppData\Local\Adobe\Lightroom CC\Data
ETA: I tried moving the photos (14+GB worth) from my SD card to an internal HD and importing them from there, and now Lightroom hangs up halfway through the import. When cancelling the import LR claims the files are "unsupported or unreadable" which is horsecrap.
ETA2: On the off chance that the photos my drone took were, in fact, corrupted, I tried using LR to load u p a batch of photos I've already used in the past which are known to be perfectly fine. Same behavior. In fact, when I go back to the batch I originally started having this problem with in Windows Explorer, Windows is having trouble generating previews and I have had to hard-reboot my PC multiple times this morning. WTF is LR doing to my photos?!
ETA3: Last week I took a batch of 530 photos and edited them all in LR using my normal workflow, and had no problems at all. I wound up not using them for what I meant to, but I also didn't delete them. I just reloaded the exact same series of images this morning and the same freezing behavior occurred after pasting edit settings, four photos in.