I have the most recent version of LR CC on Windows 10 64bit. When trying to import, either from my EOS 70D card or from the file system, the import stops building previews when a *.mov file is encountered. If you try to proceed with the import anyway, the import just hangs and imports nothing. I've read through many of the posts related to this and it appears to be a sporadic problem with no real solution. In fact, it does not happen all of the time. However, it does occur frequently.
Where is Adobe support on this issue? I've been using LR for years and have never run into a problem as pernicious as this. One gets a bit frustrated with trying to align all the planets perfectly to get this to work! C'mon Adobe! You need to start addressing this issue.