iChat uses port 5190 to login using the TCP protocol and gets certain Buddy List info back on port 5190 on the UDP protocol.
For some modems and routers this seems to be a problem.
Try opening iChat and logging out of AIM from the IChat menu.
Then go to Preferences > Accounts.
In there select the account/screen name you are using.
Select the Server Settings tab on the right.
Set the port to 443
Log back in to AIM
This makes the Login happen on port 443 instead of 5190 and separates it from the UDP data.
Another problem might be that your Login preferences held in com.apple.iChat.AIM.plist are corrupt.
Go to Users/(your account)/Library/Preferences and delete it.
This .plist will be recreated from the iChat defaults and your Keychain info.
On some occasions you will see the Start Up Screens again but the info should be pre-filled form your Address Book.
10:46 AM Thursday; July 26, 2007
Thanks for the suggestions. Both were good thoughts with very clear instructions making accomplishing those tasks simple. I had not tried either of them before and I know I would not have tried changing the port.
Unfortunately neither of the suggestions worked. I am baffled.
My wife's MacBook is sitting right next to mine, connected to the same WiFi network, we have identical Buddy Lists on our open iChats and yet she is showing one of our Buddy's online that I am showing offline. Aargh. I have tried duplicating her settings. I have tried using her account with her settings and the 443 port. Nothing gets my Buddy List to show this "Buddy" as online all the while he is showing online on the AIM on my computer and iChat on the MacBook.
Any other ideas?
I do not know how you have your Buddy lists set up.
If you real names and the link to the Address Book check the Address Book entry for both Macs.
Compare this with the Address Card of the Buddy.
Click once to highlight
Use the Apple key+i together (Get Info)
Go to the Address Card option in the drop down.
Make sure the spelling is correct. (in all places)
If it had not been for you trying your Screen name on your wife's computer I would have thought your Buddy may have been blocking you or using a client that did invisibility.
6:08 PM Thursday; July 26, 2007
Both Address Books look exactly the same EXCEPT my wifes shows a green light next to the picture of this buddy, which indicates he is online. Mine nothing.
Further info, I used her account on my computer with the 5190 port (I had set the 443 port before) and this Buddy SHOWS ONLINE!
So now I have three accounts set up on my iChat. All the accounts have the same settings and only one of them will show this buddy online when he is online.
I chatted with this buddy yesterday and made sure that he didn't have me blocked. That thought had crossed my mind. There are people out there that just don't want to talk to me. The surprising thing is my wife doesn't have me blocked!
I just tried this on my wife's desktop (iMac G5 1.8 GHz). The buddy in question does show ONLINE on her account. I added my account to that computer, signed on as me and the same buddy shows OFFLINE. When I switched the accounts back to her, this buddy again showed ONLINE!
If you are keeping score:
my wifes screenname: all computers show this buddy ONLINE
my screenname: my wife's MacBook shows this buddy ONLINE
my wife's iMac G5 shows this buddy OFFLINE
my MacBookPro shows this buddy OFFLINE
So your Buddy does not show up in your Buddy List when using port 5190 or 443.
He does not show up on your computer with the port 443 being used but does when port 5190 is.
This points to the .plist in the preference file being a bit off.
You did delete the one that has AIM in the name ?
com.apple.iChat.AIM.plist and Restarted iChat ?
And the Address Book Lists this Buddy ? (will only show Buddy with Real Names or Email info)
And their screen name is spelt right ?
After that I am stuck as much as you are.
6:56 PM Thursday; July 26, 2007
Yes, per your instructions included with your first response. I just did it again, this time emptying the trash (I did not empty the trash last time).
The problem continues with my screenname. This buddy is showing OFFLINE. When I switch to my wife's screenname, this buddy is showing ONLINE. He continues to show ONLINE in the AIM window throughout all of this. He's been very kind to stay logged on all morning.
There are several other iChat preferences that I have not touched. Could any of them be the problem?
Would it hurt anything to toss out all of these and then restart iChat just to see?
The only other .plist that might effect this is the Subnet one IF you did have him Blocked once upon a time.
There is one other possibility.
In your Screen name in AIM which group is he in ?
If it is Recent Buddies or a group you don't have in iChat he will not show up.
AIM has a Recent Buddies group where he may have been added whilst you were using that App or a PC.
iChat does not use the Recent Buddies group and therefore does not display it.
7:29 PM Thursday; July 26, 2007