How do you fix the problem when it says "Not enough space for the temp folder"?

This problem is caused by insufficient space in the temporary folder which is used to store temporary files. An easy solution to this problem is to change the temporary folder to a different folder. To do so, go to Settings > General, and change the Temp Directory to another hard drive with sufficient space, and then try again. Alternatively, delete some useless files in the hard drive that the temporary folder locates in.

Note: The recommended space for the temporary folder is at least 2 times by the size of all source video files.