No sound after upgrading to 64-bit Ubuntu 11.10

After upgrading from 32-bit Ubuntu 11.10 to the 64-bit version, the sound system stopped working.

To fix this issue, I ran

rm -rvf ~/.pulse/ 

Interestingly, it worked straight away without re-login.

Refs
http://ubuntuforums.org/showthread.php?t=1845555

Evoluation failed to append to mbox

After upgrading Evolution to version 3.2.0, I kept getting this message after sending an email from any of my mail accounts:-

The reported error was "Failed to append to mbox:///home/tom/.local/share/evolution/mail/local#Sent: Invalid folder URI 'mbox:///home/tom/.local/share/evolution/mail/local#Sent' Appending to local 'Sent' folder instead.". 

I fixed it by going to

Edit menu -> Preferences -> Mail Accounts 
-> Select a mail account -> Edit -> Defaults -> Revert

Refs
http://ubuntuforums.org/showthread.php?t=1839990