Clients unable to view their Calendar in Express - runtime error 800a01c9 User receives a VB Script Runtime error when selecting the calendar after login via express. "runtime error 800a01c9" "the key is already associated with an element of this collection." This error is due to a corrupt file within the Calendar folder. Try to locate Month that causes the issue. For example if viewing May 2009 is the problem, locate the \INBOX\Calendar\20095 folder for that user on the BOX folder. Delete the folder.imp. That should resolve the issue. The folder.imp will be recreated and no data will be lost.