- Force Quit Safari. How To: https://support.apple.com/en-us/HT201276
2. Quit Safari, launch Safari holding the Shift key down.
https://support.apple.com/en-us/HT203987
3. Startup in Safe Mode. https://support.apple.com/guide/mac-help/start-up-your-mac-in-safe-mode-mh21245/mac.
Login to your account, launch Safari to test.
If you can, Clear History.
Quit Safari.
Logout.
Click the the "Restart" button at the bottom.
Safe Mode
Quote:
It also does a basic check of your startup disk, similar to using First Aid in Disk Utility.
And it deletes some system caches, including font caches and
the kernel cache, which are automatically created again as needed.
Test Safari.