I was trying out Apple’s new MobileMe service and I was having a hard time registering my computer for sync. I would click the Register button and things would spin for a while and then nothing. No error message of any sort, it would just stop and the registration would fail. After searching log and hard on the web, I found an article that offered a number of potential solutions. It turned out my problem was a series of entries in my /etc/hosts file for mac.com. I edited the file and removed the entries and voila, registration worked.
Do the following:
1. Type ‘sudo nano /etc/hosts’ in the terminal. Type your admin password.
2. Delete any line that is related to dotmac. By default /etc/hosts contains only four entries.
You can easily delete them from the command line by using the arrow
keys to get to the right line, then press CTRL+K to cut them out.
Save the file (CTRL+O then ENTER) and close the terminal window.
3. Either wait for the OS X DNS server to reload the file, or restart your computer. I did the latter, just to be sure.