Arc keeps a profile per space, and archived tabs never really leave
Arc stores profiles, spaces and an archive of every tab you have closed. Where the data is and which parts are safe to clear.
Arc is built on the same engine as Chrome, so its storage behaves the same way with one addition: spaces and profiles multiply the parts that already grow. A browser with four spaces across two profiles keeps several sets of the same kinds of data.
Where it is
du -sh ~/Library/Application\ Support/Arc 2>/dev/null
du -sh ~/Library/Application\ Support/Arc/User\ Data/* 2>/dev/null | sort -h | tail -10Inside User Data there is a folder per profile, each with the familiar Cache, Code Cache, Service Worker, IndexedDB and Local Storage. That structure is worth recognising because it is identical across every Chromium browser, and the same advice applies to all of them.
What is safe, and what is not
| Folder | Holds | Clearing it |
|---|---|---|
Cache, Code Cache, GPUCache | Pages, scripts, images | Slower first load |
Service Worker | Offline data for web apps | Web apps resync |
IndexedDB, Local Storage | Site state and sessions | Signs you out of sites |
Default/Extensions | Installed extensions | Uninstall through the browser |
| Profile folders | Everything for one profile | Removes that profile entirely |
The archive
Arc archives tabs rather than closing them, which is the feature people like and the reason its database grows steadily. The archive lives in the profile database, and clearing it is done in the browser rather than by deleting files. Its setting for how long tabs live before archiving is the lever worth changing once.
Do it across every browser at once
Most Macs have three or four browsers installed and one in daily use. The other three are still holding their profiles, and that is the fastest win here:
du -sh ~/Library/Application\ Support/{Arc,Google/Chrome,BraveSoftware,Microsoft\ Edge,Firefox} \
2>/dev/null | sort -hChrome measured 8.1 GB on a real Mac, most of it profiles rather than cache, and the same pattern holds here. Firefox keeps old profiles forever too, which is worth checking on the same pass.
Common questions
Where does Arc store its data on a Mac?
In ~/Library/Application Support/Arc, with a User Data folder containing one directory per profile. Inside each are the standard Chromium folders: Cache, Code Cache, Service Worker, IndexedDB and Local Storage.
Is it safe to clear Arc's cache?
Yes for the cache folders, which rebuild as you browse. Clearing IndexedDB and Local Storage signs you out of sites, and removing a profile folder takes its history, logins and extensions with it.
Why does Arc use more space than expected?
Because spaces and profiles multiply the data a browser already keeps, and archived tabs remain in the profile database. Several profiles mean several complete sets of caches and site storage.
How do I compare browsers by size on a Mac?
Run du against the Application Support folders for each browser you have installed. On most Macs the browsers no longer in daily use are still holding full profiles, which is the easiest space to reclaim.