Has this happened to you?
Were you processing your mail filters then emptyied the trash? Suddenly your Inbox was empty!!!
Here is how to fix it on Fedora Core 14:
[root@MYCOMPUTERSHOT]#rm -f /home/[MYUSERNAME]/.local/share/evolution/mail/local/Inbox.ibex.index
[root@MYCOMPUTERSHOT]#rm -f /home/[MYUSERNAME]/.local/share/evolution/mail/local/Inbox.ibex.index.data