Outlook 2010 has a limit of 30 calendars selected at any one time. If you try to select more than 30, you’ll be alerted: “More than 30 calendars cannot be viewed at once.” It’s surprising to have a limit because Outlook 2010’s Schedule view makes viewing large numbers of calendars much easier – in older versions it was difficult to view more than 13 to 15, even using overlays.
If you need to view more than 30, create smaller calendar groups and select/deselect the groups as needed. Yes, it’s not the same as viewing all at once, but you can view the groups you need with just a few clicks.
More calendars can be configured in the registry using one of the following keys:
DWORD: CalendarMaximumNumber Values: 40, 50, 60, 60, 70, 80, 90, or 100 (decimal)
We have ready to use *.reg files for 40, 50, or 60 calendars at View more than 30 Calendars in Outlook 2010
Published May 21, 2010. Last updated on March 14, 2012.