In the folder…
C:\Users\<user>\AppData\Local\Google\Chrome\User Data\Default\Service Worker\CacheStorage
…Chrome keeps piling up 20+ GB every few months like clockwork. Other browsers don’t pull this kind of crap. I have to clean it out manually every time.
And yeah, this isn’t the regular image cache, it’s service workers. What happens: when you visit a site, the browser can register a background process — a Service Worker. It runs independently of tabs and lives in the background to provide offline access (which I absolutely don’t need), faster page loads (I turn that off lol), push notifications (ALWAYS DISABLED, hello?? stop clogging up my computer!), and other cursed PWA stuff (Progressive Web App = “progressive” my ass web app). Basically, pure hell.
This mechanism has its own CacheStorage API. Unlike the standard HTTP cache, where the browser decides what to keep and when to clear it, here the site itself ( sic! ) is in control through JavaScript. That means the page code can say: “dump these 100500 MB of scripts and images, plus a dozen video chunks, plus some JSON data,” and the browser, like a good little idiot, will obediently stash it all into CacheStorage. So you end up with literal copies of site resources on disk, including freaking video files. No, it’s crazy useful… but there should be some damn limits, right?!
Why does this bloat specifically in Chrome?
Because Chrome’s quota policy lets CacheStorage eat up to 80% of the free space on the system drive (the cap can reach 50–100 GB). And until the user cleans it manually, the junk just sits there. Meanwhile, holy Firefox is stricter: its caches get trimmed faster and don’t swell into dozens of gigabytes.
How exactly?
Architecturally, every “domain origin” (site) gets its own namespace in CacheStorage. Inside it’s a key-value store built on top of LevelDB (keys are resource URLs, values are binary blobs with content). And Chrome the beast dumps all that straight onto disk in that folder.
It’s done in the dumbest way. There are no automatic “clear old stuff” policies until forced eviction kicks in, which only happens when the disk is on the verge of running out of space.
And the funniest part — you won’t even see any of this in the browser settings. There’s a “clear cache” option, but it only wipes the regular HTTP cache. CacheStorage keeps living its best life. So the user thinks they’ve cleaned everything, but in reality there’s this secret garbage warehouse sitting on disk, courtesy of service workers.
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