VLC taking half a minute to play an MP3? It probably isn't VLC's fault

Thirty-three seconds to start playing an MP3. That was game designer Jonathan Blow's complaint on August 12, posted alongside the news that he'd switched to Windows' own media player and a broadside about the state of open-source software. VideoLAN, the group that makes VLC, answered within a day with a different diagnosis: a Microsoft Defender update on Windows 11 had quarantined VLC's plugin cache.

That one file explains the whole delay. VLC isn't really a single program - it's a few hundred small plugins, one for each video format, audio codec and input type, and it keeps an index of them in a file called plugins.dat. With the index in place, VLC opens instantly. With it missing or blocked, VLC re-scans the entire plugins folder every single time you double-click a file. Hence the wait, and hence the fact that it feels like the app is broken.

Three fixes, easiest first. Reinstalling VLC from the official installer at videolan.org rebuilds the cache. If you'd rather not reinstall, VLC ships a small tool called vlc-cache-gen.exe in its program folder that regenerates the file on its own. And if the slowdown keeps coming back, adding VLC's folder to Defender's exclusion list stops the cache being quarantined again - worth doing only for software you're certain about.

Being straight about the limits here: Microsoft hasn't confirmed any of this. There's no KB number, no Defender detection name, and people on Windows 10 report the same lag, so the plugin cache may not be the whole story. Rebuilding it fixes the problem for most people who've tried.

If reinstalling apps is your usual repair move, Tendvane's app updater goes through Windows' own package manager (winget), so VLC and everything else comes from a trusted source rather than whichever download site a search happens to serve up.