Where is the VLC log?
The VLC media player sometimes errors out with the message "Check the log for details":
But where is the log?
What you need to do:
<Ctrl>-Mor click Top Menu => Tools => Messages
Increase the verbosity to "1 (warnings)":
(You could increase the verbosity even more, but that might create so much output that you cannot find the actual error anymore.)
Leave the messages window open and recreate the problematic behaviour