Can't play *.quicktime file using quicktime player

I am trying to play a Quicktime Video File (*.quicktime) using the Quicktime player but it won't play. I hear the audio but the screen remains blank. Quicktime tells me I need an extension, but I have no idea what extension.

By definition, a QuickTime file is any data content in an MOV file container. Since any compression format compatible with the original creator's system configuration, including third-party proprietary or non-Apple supported formats like Xvid, DivX, WMV, etc,, can be wrapped in an MOV file container, you need to open the "Inspector" window to learn what specific codecs were used to create the problem file. As to extensions, these are usually 3 (or more) characters following the dot/period at the end of a file name. extensions can be visible or "invisible" depending on your system preference settings. Since extensions can be changed manually by a user, they may or may not correctly reflect the true file container which can also sometines present playing problems.

Also, I need to convert this file to a format that will allow me to upload the file to YouTube.

A file cannot be converted until such time as it can be read/played correctly on your system.

I came over the same kind of file which wouldn't play on any application on my mac which had me baffled as well. I finally tried re-editing the file from *.quicktime to *.mov and the problem was fixed! From there the file was easily converted.