Often I have found the user profile service in SharePoint 2010 can have some problems. On many occasions I have had to look at the client on the SharePoint server to see what is going on as this client can often give more information about this process than the standard sharepoint messages and error logs.
For easy reference, the path to access the client is here:
C:\Program Files\Microsoft Office Servers\14.0\Synchronization Service\UIShell\MIISClient.exe
For easy reference, the path to access the client is here:
C:\Program Files\Microsoft Office Servers\14.0\Synchronization Service\UIShell\MIISClient.exe
