When Safari ignores your preferred File download location setting, terminating the com.apple.Safari.SandboxBroker process can resolve the issue.
Credit to Saagar Jha, who noted the problem and solution:
I hate that my one skill with computers is finding which daemon I need to kill to make things work again
— Saagar Jha (@_saagarjha) August 24, 2025
(Today I found that if Safari is not respecting your “File download location” preference, that’s https://t.co/Cj7K2yNQOO.Safari.SandboxBroker)
Open a terminal and run the following command to kill the SandboxBroker process:
killall com.apple.Safari.SandboxBroker
kill -9 ...(ps | find "com.apple.Safari.SandboxBroker" | $in.pid)
Tip
This technique only touches Safari’s helper daemon; it doesn’t delete preferences or reset Safari itself.