Just got my new computer and wanting to migrate all my application and files seemlessly including my Yahoo Messenger. I searched the web and found these 4 easy steps:
1. First, log out from the Yahoo Messenger and close the application. This will make sure that no changes will be done to the archive that you want to transfer.
2. If you are using Windows XP, go to C:\Program Files\Yahoo\Messenger\Profiles. You should be able to see folders corresponding to each Yahoo Messenger usernames. Open the folder corresponding to the username that you want to transfer and you will find a folder named “Archive”. The “Archive” folder contains the history of your conversations.
3. If you are using Vista or Windows 7, go to C:\Users\(windows_username)\AppData\Local\VirtualStore\Program Files\Yahoo!\Messenger\Profiles. Similarly, you should see Yahoo Messenger username folders. Go to the username that you want to transfer and you will find the “Archive” folder. This folder is what you are looking for.
If you cannot see the “AppData” folder under C:\Users\(windows_username)\, then your computer is set to hide system folders. Click the link below if you are not sure how to show hidden folders.
4. Copy the “Archive” folder and place it on the same directory on the other computer that you want it to transfer. Now, there are several ways of transferring the “Archive” folder from one computer to another. You can save it on a USB flash drive, zip the folder and email it, burn it in a CD, or use other removable storage device. But the most important thing is you will place it on the same directory or location where you copied it. Keep in mind also that if you have message archive on the other computer, it will be overwritten so you may want to backup that archive first.
Thanks to eHow for this helpful info.