Many times when I download a media file, video or image, I can use the file once. Then when I return to the media list I find that there is an explanation mark outlined in yellow and I can not longer use the file so I have to delete it and reload to use it again. Usually the same thing happens. The media files often covert
from useable to not useable. Why?

It happens when media is not in same folder as it was when originally added to EW. Need more information about steps taken to download and add to EW; plus what happens before disappearance (power off/reboot/file maintenance/etc.)