Event Viewer Log:
Failure trying to synch web application cbe312cd-9f86-4309-affd-7fe0489faa7e, ContentDB 6586aeed-aa81-45c8-911a-7e193b672d9b  Exception message was A duplicate site ID 41ca7ec3-0fad-4db2-883f-62c707f1cd6b(http://portal:8000) was found. This might be caused by restoring a content database from one server farm into a different server farm without first removing the original database and then running stsadm -o preparetomove. If this is the cause, the stsadm -o preparetomove command can be used with the -OldContentDB command line option to resolve this issue.

Cause/Description:
Table “sitesynch” in the sharedservices database is responsible for the errors caused by the hourly profile synchronizations service.
The database id‘s  in that table do not match with the database id’s from the config database of the SharePoint.
This table might not be updated when the content databases were detached and attached (could be a bug in SharePoint).

Workaround:
1. Go to SharedService Database
Select * from sitesynch, clean up the table
After deleting the rows from this table the errors gone away and the table is re-populated back with correct sites and database id’s next service ran (usually hourly), or
2. Run this command: stsadm -o sync -DeleteOldDatabases 0