I have several users that a working on Macs in a corporate Windows Environment (Exchange Server) all running the latest version of Office Outlook 2011. Some of the Administrative Assistants have been having issues while trying to manage their Bosses shared calendars. Randomly all the color / categories will disappear from the Bosses calendar for both the boss and the assistant. For example all the Travel events will be coded to Red but every couple of weeks the colors are all reset to one default color.

Is there a work around or a setting that will keep this from happening? Is it something that the users are doing that causes all of the colors to be erased? I can’t seem to find anything online that speaks to this issue and this is causing End User and IT Support friction but I am not really sure how to resolve it since I can’t even narrow down the cause.  

Any suggestions would be appreciated.