Without knowing what version of Outlook, the view you are using, how you are trying to group your categories, or anything else, no idea whatsoever.

Go fish!

--�
Milly Staples [MVP - Outlook]

Post all replies to the group to keep the discussion intact. All
unsolicited mail sent to my personal account will be deleted without
reading.

After furious head scratching, gofish asked:

| I am having trouble sorting by categories.
|
| I keep getting the message: The sorting or group by operation failed.
| Either these folders do not support sorting or the conditions are too
| complex. Sorting and group by settings have been reset.
|
| Any ideas????