Users often complain about the patchwork look of Outlook's calendar. This is caused by setting All Day Events to Show time as Busy and setting a color category on the item.
All Day events marked as Busy highlight the day with the category color. If the event is not assigned a color category, the day shading uses the calendar color.
Items marked with hash lines are Tentative. The hash lines are the category color, or if no color category is assigned, the lines are the calendar color.
Items marked Out-of-Office are always purple, with the block around the appointment text using the category color.
Timed appointments are shown in the category color and the Free/Busy indicator is shown in a small bar to the left of the appointment.
The new Outlook 2013 Working Elsewhere status uses a dotted background.
Timed appointments and color categories
Timed appointments are displayed in the category color with the Free/busy status shown in a small bar on the left side.
Outlook 2013 adds a new Free/Busy status: Working Elsewhere, which uses a dotted pattern in the Free/busy indicator on the left.
Busy appointments use a darker shade of the category color.
Tentative appointments have hash marks on the left.
Working Elsewhere appointments have a dotted pattern.
Free is white.
Out-of-Office is purple.
Outlook 2010's Free/busy indicators.
Busy appointments use the category color.
Tentative appointments are displayed with hash marks on the left.
Free is white if you have all updates installed, otherwise, it's a lighter shade of the color category.
Out-of-Office is purple.
Note: Working Elsewhere isn't a Free/Busy option in Outlook 2010 or Outlook 2007, but Exchange mailbox users will see items marked for working elsewhere with a black bar in the Free/Busy indicator if they open their mailbox in Outlook 2010 or 2007.
Outlook 2007's Free/busy indicators:
Busy appointments use the category color.Tentative appointments are displayed with hash marks on the left.
Free is white (Outlook 2007) or a lighter shade of the color category (Outlook 2010).
Out-of-Office is purple
Day and Week calendar colors
Day and Week calendars are also shown in the category colors when All Day events are marked busy or purple when the event is marked Out-of-Office. As you can see in this screenshot, when no category is assigned to an all day event, Tentative and Busy (and Working Elsewhere) shading is picked up from the calendar color.
Unlike previous versions, Outlook 2013 does not shade non-working hours or non-work days (as in Calendar Options).
The blue line across the days indicates the current time in Outlook 2013's day and week views.