A user working with shared calendars has a problem with color categories: she wants to color code appointments but she can’t add her categories to appointments on the shared calendars and she can’t add new categories to the shared calendars as all of the color category options are grayed out. Adding new color categories while working in her calendar makes them available for her appointments but not for the appointments in the shared calendars.

As she discovered, Outlook only allows categories to be created by the mailbox owner. If a user wants to add more categories they need to open each mailbox directly (i.e., using the owners username and password). Once the color categories are added, they will be available for anyone to use them when creating appointments in the calendar.

However there is a workaround you can use to avoid too much extra work on the part of the mailbox owner and it won’t require you to use their username and password to open the mailbox.

• First, make sure the categories you want to use are in your master category list.
• Next, create an appointment in your calendar and add all of the categories you want to use with the shared calendar to it.
• Then copy the appointment to the shared calendar. Categories not in the owner's master list will be colored white.
• Finally, ask the mailbox owner to right click on the mailbox and choose Properties, then click ‘Upgrade to color categories’.

Once they do this, it adds them to the master list (with colors assigned in the order Outlook chooses) and you'll be able to use the color categories and even change the colors. (If using cached mode, you many need to wait a few minutes for the colors to update on the server.)