Hi,
This is an old post that only applies to the Mountain Lion version of Messages.
The info I was talking about is now stored in a new .plist.
Generally speaking you can change the info in the App and it tends to be permanently saved to the plist on closing the App.
Some info is Written to the .plist straight away.
It is also slightly more complicated now as the App is a Sandboxed one which means if it Crashes it does not bring down the whole OS with it.
This in turn means there is a Read and Write route as well as the end storage .plist
Do this bit from earlier:-
Have the Finder as the "front" app.
Go to the Go Menu > Go to Folder and type in ~/Library/Preferences into the Dialogue box that appears.
Once in the Preferences set it to Cover Flow view.
Now go to the View Menu > View Options and tick the Modified item.
If not displayed already a Modified column should be added.
Click the Modified title and that column will become the search/Display criteria.
The Preferences file is where you will find the com.apple.ids.service.com.apple.madrid.plist file.
You can use Quick Look to read the file.
You need to see this line and the details below it.
This is fairly near the top and lists your Apple ID as the Signed in account name and then list the the Aliases for "Receive At".
If you have other Unselected ID/Emails they will also show here.
There is a spot further down about Vetted Aliases that repeats the same info.
The earlier post I made says to tick the Modified Column to use that as the info/search listing for the window's info.
It should look like this when the app is started.
When you change the settings in the Preferences > Accounts for the iMessage Account the "madrid" .plist should come to the top.
To Write to this .plist the app uses the Path ~/Library/Containers/com.apple.iChat/Data/Library/Preferences and then an Alias that is connected/points to ~/Library/Preferences/com.apple.ids.service.com.apple.madrid.plist
You have to have Ownership and the rights to Read and Write to not only the end file but also all the containing Folders.
Go to the Alias listed above and check it opens the "madrid" .plist.
On each of the Folders Right Click and chose Get Info.
At the bottom of the Info panel is Ownership and Permissions.
Your shortname (Mac User Account name) should be listed.
Highlight that then use the Cogwheel type icon under the list.
This should list you as the Owner by being Greyed Out.
Your listed name should say it can Read and Write to the File and Folders depending which one you are looking at.
7:59 pm Saturday; January 23, 2016
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