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I want to update the schedule in /System/Library/LaunchDaemons/ I have unlocked the file in Finder but the Property List Editor is giving me:

The file "" could not be unlocked.

Could not add write permission to the file because you do not own it. Try modifying the permissions of the file in the Finder or Terminal.

I don't want to make myself the owner of a System file. Is there a way to edit this file without manually changing the permissions?

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Couldn't you just use a code editor? At least TextMate and TextWrangler can convert property lists from binary to XML and authentificate as root in order to save files.

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Hmmm, I downloaded TW and that worked. I am wondering why I can't do this with standard Apple software. I would prefer not to have to use a third-party application to do this. I like the structured editing of the PLE. – Stephen Rasku Jun 29 '12 at 17:32
up vote 0 down vote accepted

I was able to edit it by enabling the root user and editing it directly as root with the PLE.

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Now that Property List Editor is part of Xcode, the easier solution may be to change ownership of the .plist and containing directory to your user account temporarily while you edit the file, then change back. I'm surprised Apple didn't seem to think of this. – duozmo Oct 17 '13 at 6:00

I usually do

cp /System/Library/LaunchDaemons/ /System/Library/LaunchDaemons/
cp /System/Library/LaunchDaemons/ /tmp
# run PLE on /tmp/
sudo launchctl unload /System/Library/LaunchDaemons/
sudo cp /tmp/ /System/Library/LaunchDaemons/
sudo chown root:wheel /System/Library/LaunchDaemons/
sudo launchctl load /System/Library/LaunchDaemons/

or (if in a hurry) I just change file ownership, do the edit and change ownership back to the original setting.

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Lingon is a great App with a nice UI for managing these types of files.

No hassle other than authenticating at file save.

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