I'm not sure why, but on my mac (both at home and at work), Chromium's start up time seems to get worse over time.
If you allow Chromium to sync everything then there's a fairly simple way to speed it up again - quit Chromium, and simply delete (or rename if you want to be careful) your ˜/Library/Application Support/Chromium folder. Restart and enable syncing by entering your password. After a short while everything should be back to normal, but next time it will start a lot quicker.
The only thing that seems to be lost is your recent tabs on the new tab page...
Somebody # 05/06/23 16:46