Unsticking Stuck Preference Settings
Preference Domains, one of the least understood parts of the whole system, are detailed here. In practice, this means there may be another Property List in ~/Library/Preferences/ByHost which is overriding that in ~/Library/Preferences. The property lists in that ByHost folder are named differently, such as com.apple.loginwindow.[UUID].plist. The UUID used corresponds to that of your Mac’s Hardware UUID, which can be found at the top level of System Information.
[…]
If you have got a stuck preference setting, once you’ve ensured that it isn’t the result of incorrect permissions on that preference file, you need to discover the key name for that preference, whether it’s global or from an app-specific domain, then use
defaultsto look for an overriding setting with the-currentHostoption. If you find that, usedefaults -currentHost deleteto remove that override, and your normal setting should start working again.
Update (2022-11-30): Howard Oakley:
Sometimes, even using
defaultscarefully can’t unstick a preference setting. What you probably never even dreamed is that preferences have an overriding hierarchy, and what may have happened is that the preference you tried to set was already being overridden by a Property List with a higher priority. If you can discover how to undo that, then you should still be able to change the setting that’s been driving you crazy.
