Hi, I have about 5,000-6,000 images, mostly iphone camera jpegs, and a few videos (4k iphone videos), and a few (really not many) live photos, for which, incidentally there is still no proper support in LR. I have observed the issue of thumbnails in the import pane not showing previews literally for years, in several former LR versions, and with several previous iphone models, and the bug is still here now! Sometimes I could make LR render most of the thumbnail previews by repeated restarts of the app and by starting import afresh several times. This bug is only present if you have over 1,000-2,000 images on iphone. Now the total freeze of the import is a new "feature" that appeared couple of months ago. Also, I have observed that if my iphone import hangs like this, I cannot exit LR normally, I have to force quit.
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