VLC will not exit when failing downloading album art
In a environment that network is not available, open a video file with VLC, and closing it. VLC will not exit normally, it will remain in memory. (Using ps aux command can prove that) Only killall -9 vlc can end it.
This is caused by "Album art download" feature. If the option is set "As soon as track is added"(by default), VLC will try to fetch album art when opening a video file. When the network is unavailable at this time, (In my case, this computer is connected to a wireless router, but the router has no Internet access.) it will stuck.
After changing the option to "manually download only", VLC will not stuck on network unavailability.
This bug will prevent a removable media from rejecting after playing a video file in the media with VLC.