Q: QuickTime is saying "operation stopped" when trying to share to Youtube. Why?! And How do I fix it!?

Stop trying to 'share to Youtube' & look for a better way to backup your data.

Your task will keep failing for this reason… Quicktime can convert your movie to another format for Youtube, this takes disk space - you already have too little disk space, so the operation fails. If you keep trying you may simply make the disk too full to startup correctly!

A better solution is to find a USB hard disk or even a flash drive & save files onto that so you can delete the files on your disk to free space. Operating with no free space will cause many weird issues.

There are many apps that will copy your entire disk - ask if you nee help with that. Creating a bootable backup is the best way to avoid losing data. Relying on Youtube to keep important files is a terrible idea - they often take files down if copyright infringements are found etc.

I haven't witnessed this issue firsthand so if Quicktime is 'locked up' and unresponsive you really don't have much choice I'm afraid once it is deadlocked there is little you can do to make it save work. If you are lucky the app may restore it's open files after a reboot but that is a risky option - it may not save the state if it has crashed.

If it isn't frozen or you can cancel the current task try the export option in the file menu. It should allow you to save to another disk if you choose an option like 1080p or an appropriate size. I suspect it still may want to save some data to the system disk, however it may work if you have an external disk to save onto instead of relying on the system disk alone.

You can also quit other apps in the hopes that they free up some disk space but I doubt that will help at all.

You could look at the default locations where Quicktime stores recordings, I think screen captures are saved in [HOME]/Library/Containers/com.apple.QuickTimePlayerX/Data/Library/Autosave Information, but I am using a different OS X version so that may have changed. You need to select this in Finder, "Go > hold 'alt' & click Library" to see the hidden Library folder contents. I don't know if other recordings are saved there too.

It may help if you describe how you created these files, it's possible they may exist somewhere out of site that you can recover later.

A property list (files ending in '.plist') is just a special text document that Apple use to save general data in OS X, in this case it is just some 'metadata' about the file(s) that are open. You are looking for a movie file in that location.

Since you haven't told us how you made this movie (e.g. screen capture, iSight camera, imported files etc) it is entirely possible that the file is not saved into that location. If you made the movie or edited one that exists somewhere else it may not be kept in the autosave folder.

Sorry, I don't know what will happen when you reboot. I'd suggest you try to capture as much as you can before doing that (e.g. photograph the failed screen so you can explain what happened to your teacher etc). If the Quicktime window will playback record that via a camera to help you recreate the movie, or show that as evidence that you did the work. I'm assuming you are making it for a course with a teacher that may understand how computers can go wrong.

I'm afraid that unless anyone has a better idea, you may need to just 'bite the bullet' & reboot to see if the file is reopened. The sooner you do that the sooner you can try recreating it or explain why it doesn't exist - it isn't entirely clear to me why you can't remake it.

I just recorded a movie from an attached camera in Quicktime & it appeared in the same autosave location as I mentioned earlier.

Sorry I'm out of ideas, you can hold on to see if anyone has a better idea but I think it's gone. I'm not sure where the work in progress for share to Youtube is stored, it's probably within a temporary files location, but those can be impossible to piece together.