Configuration Profiles using Set-Once are destructive

Number:rdar://19964383 Date Originated:25-Feb-2015
Status:Open Resolved:
Product:OS X Product Version:10.10.x
Classification:Data Loss Reproducible:Always
Installing a Profile on 10.10.x using the frequency of Set-Once with no timestamp (equivalent to the "Often" setting from MCX) the preferences the profile controls, plus whatever was set at the time of the Profile installation, are applied every login and destroys any changes made to the domain's settings since the profile was applied.  This same profile behaves properly in OS 10.9 when installed and only refreshes the preferences in the Profile payload.

The Often setting had been used successfully in the past and is mirroring the MCX payload model.  The Forced and Once (Set-Once with a timestamp) method still behave as expected.

Steps to Reproduce:
1. Create a plist with settings:
 `defaults write setting1 -string foobar`
 `defaults write setting2 -bool false`
`defaults read` to see the applied settings

2. Use Tim Sutton's mcxToProfile tool to create a Profile to manage the domain “often”. ` --plist ~/Library/Preferences/ --identifier MyGreatApp --manage Often`

3. Delete the settings to clear the slate
 `defaults delete`

4. Install the profile on a computer running Yosemite. 
`sudo profiles -IF MyGreatApp.mobileconfig`
`defaults read` to see the applied settings

5.  Make some preference changes after the Profile was installed:
`defaults write setting3 -string Chickens`
 `defaults write setting4 -int 42`
`defaults read` to see the applied settings

6. Log out and back into OS X and read the plist again.
 `defaults read`

Expected Results:
The settings applied after the profile was installed would still be present after logging out and back in.

Actual Results:
The user’s settings made after the profile was installed have been eradicated even though they aren’t the keys being managed.

10.10.3 14D87h

Additional anecdotal information can be found at

The mcxToProfile tool is at and is commonly used in the Mac admin community.

This happens on 10.10.2 GM and 10.10.3 14D87h
This does not happen on 10.9.5


Addressed in ElCap?

I was asked to verify the behavior in ElCap beta 4. To my surprise the set-often profile is behaving as expected again. I've asked if the set-once/set-often frequency is supported. We'll see if they answer.


Did you ever get a reply if the set-once/set-often frequency is officially supported?

By richard.uurazzle.glaser at July 14, 2017, 7:10 p.m. (reply...)

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