Collaborate recordings are not permanently available for either viewing or downloading. If you wish to keep a recording from term to term (and class to class), you should download these files and utilize other video-sharing options to share videos with students. For example, use
Yuja Media Library.
Within the Collaborate Recordings view, mouse-over the three dots to the right of the video you wish to download.
Choose download.
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This will open your downloads or documents file (Finder on Mac and Windows Explorer on PC). Save the file with a unique title and in a place you can later find. The file will save as mp4, which is compatible with most video sharing and viewing platforms.