User Profiles not Synching after an Upgrade to Sharepoint 2010

Hi .
an issue was brought to my attention from 1 of my clients ....
after an upgrade the users were not receiving any alerts or emails when tasks were being assigned.
ok ..so first port of call being to check and see exactly where things go pear shaped .....
I looked at he exchange event logs and found out  that the email message is coming through but with all the wrong email address .... weird  ...so a full AD Sync was done and still the issue persists ...
hmmm ..... *scratching my head ...*
then i started looking at the 2007 Plumbing which the upgrade was built on ....
i then found the user list  ......and PRESTO ......this is where it was getting all the OLD email values ...

SOLUTION:
Delete the entries in the user list and Re-Sync the AD ... this is what solved my problem .. :)

Regards
Bradley