HI,
Actually.
Delete com.apple.imservice.imessages.plist and com.apple.imessages.bag.plist and not all the iChat ones.
These two specific ones for the iMessages account in Messages deal with the Apple ID that has been used and the Server that the Login is trying to get to.
For your info.
com.apple.ichat.plists holds all the Preferences Settings except accounts and some Menu items like the Style, Show Smilies, Show Video or Audio Status.
com.apple.ichat.aim.plist only holds the logged in Status of any AIM Screen Name or AIM valid name.
For instance if your System Crashes whilst Logged in the AIM Servers will notice you "left" and set you Account to Off line.
However when you relaunch the com.apple.ichat.AIM.plist tries to say you are logged in.
You can obviously have issue around this.
The com.apple.iChat.Jabber.plist does the same for all Jabber Logins (GoogleTalk, Facebook and other Servers)
com.apple.ichat.Subnet is about whether your were using the Bonjour account.
The SharedLists one is about the Recent Chats Lists.
The Saved Status Messages "does what it says on the tin"
com.apple.imagent.plist Holds the iTunes Playing data order info.
See this older iChatAgent tip at MacOSXHints You have to change the ichatagent bit to imagent.
It also holds the info about whether the camera, Mic an Screen Sharing (which iMessages cannot do) are active.
9:03 PM Friday; August 16, 2013
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.4)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously