Comment 15 for bug 43233

Sorry, have to correct myself... you _can't_ actually use "sudo rm /var/run/sudo/yourusername/*", because the shell will fail to interpret the wildcard and will tell you that the file or directory doesn't exist.

So, you have to remove the timestamp files individually, giving their proper names, or - more efficiently - do "sudo su" followed by "rm /var/run/sudo/yourusername/*" and "exit".