internet – 4 GB of disk space goes “missing” for a week after browsing away from standard sites, why does this happen?

Using Stack Exchange, reading the news, watching a few YouTubes, browsing journals does not cause this. But when I go off into clickbait and less reputable sites my laptop’s fan starts running, memory runs out and about 4 GB of disk space becomes unavailable.

In a week or so (after several restarts), the space becomes available again.

I’m not asking which program to download to recover the space, I’m just curious if this stealth disk squatting is a known phenomenon, what might cause it, and how I might discover myself where that space is and clear it out.

  • macOS 10.11 (yes I know, will address this soon)
  • Chrome browser
  • MacBook Air (Mid 2012) (yes I know, will address this soon too!)

update: I did a quick check with CleanMyMac and while it does find some things, it does not find 4 GB. When I remove 0.5 GB this way or delete files, available disk space actually reduces further rather than increases. Strange!

CleanMyMac screenshot