macOS · Mac · Speed & performance

Give Safari a proper clean-out

Safari accumulates website data, extensions and cache that quietly slow every page down. A five-minute pass brings back the speed you had in January.

Before you start

Low risk. This change is reversible — you can return to the previous state without professional help or data loss.

Safari → Settings (or Preferences) → Privacy → Manage Website Data → Remove All — this clears cookies and cached files for every site
Same settings window → Extensions tab → disable anything you haven't used in months; each one runs on every page load
Close the tabs you've been hoarding — Safari keeps a live process per tab, and 40 tabs is 40 mini-apps
Still sluggish? Settings → Advanced → tick 'Show Develop menu in menu bar', close all windows, then use Develop → Empty Caches

Safari loads pages at its old speed, and website data/extensions you removed no longer appear in Settings.

Safari is still sluggish after the clean-out — close hoarded tabs (each runs a live process) before assuming hardware limits.

Next stop: the related fixes below, or start a guided diagnosis.