As the subject line says, PSE -- when it is not freezing up -- selectively declines to import some MOV or HEIC files (*most* of them seem fine).
I don't suppose there is a fix for this that works? (Tried the Adobe Help suggestion of downloading stuff from Microsoft and deleting cache files but that didn't work)
A .mov file is a container file that can contain all kinds of other streams of video, audio and text (for subtitles), with diferent codecs. So, not all mov files are created equal. And HEIF files, including .heic files can also be either images or image sequences (video).
So, to try to solve your problem, are all of the mov and heic files from the same device? Which device are they from? Are they photo or video files? And more particularly, what are the difficulties you are having in importing them? What error messages are you getting?
There is a known problem in importing HEIF files from an iPhone to the Organizer using the Adobe Photo Downloader. But this problem seems more to do with an Apple problem than Adobe. Depending on your responses, I may be able to give you some suggestions to get the files onto your computer.
My photos and videos are organized into folders (by year, then by subject). There doesn't seem to be any obvious reason why some are imported (from OneDrive, where I store everything) and why some are not.
Take, for example, a folder containing something like 500 photos and videos of my granddaughter. On closer inspection, some are configured as (for example): 123456789.MOV. Others are 123456789.IOS.MOV. (The underlining is mine.) Both sets were taken on an iphone; some taken on an iphone XR; the others, I think, were the iphone 8. There seems to be no difference, however, in which photos won't upload.
The error message says the file is damaged or in a format that cannot be included in Elements Organizer.
If I open the folder on OneDrive containing the videos, I notice that while there are thumbnails for most videos, there are just blue icons for a few (which, if I then click on, they work). But there does not seem to be any relationship between the blue icons and the thumbnails, on one hand, and the blocked videos on the other.
I searched online help and downloaded and installed the Microsoft files -- that made no difference either.