Update : Read How to disable Building Font Cache Dialog of VLC Player
After you installed VLC player and run it for the first time by opening any media file in VLC you will see Building font cache dialog box saying “please wait your font cache is rebuilt.This should take less than few minutes”.After couple of minutes video file will be played without any problems,lot of people wonder why this happens.
I have faced this dialog box only once that too after installing and running VLC player for the first time.This will happen every time when you first play VLC Player with any file/stream after its installation.
VLC rebuilds font cache to show subtitles for files/stream which are shown at bottom of screen while playing.
If Building font cache dialog box hangs showing progressing bar each time whenever you play a file in VLC, type %appdata% in Run command box and press enter and delete VLC folder .This will make VLC to freshly rebuilds font cache again after that you will be able to play files in VLC player without any problems.
And also make sure you are using latest version of VLC media player which comes fixed with lot of bugs like these.You can find update for VLC player by clicking Help menu and clicking Check for Updates.