I have a spreadsheet in which several people enter data throughout the day.
Occasionally, a user will change another user's numbers. This is NOT good,
and I need a way to track which data has been altered. I am tracking users
by their Windows login (variable is uName), and entering their initials in
column P. Each user has a unique cell color, which is also entered in column
P.

I'm having a tough time figuring out the next step though. Locking cells
would be counter productive. I would like to insert some worksheet code
which would immediately detect if a user has changed a previous user's data,
by coloring the changed data cell with the current user's unique color.

Example:
User #1 enters 5 in cell D2
User#2 changes the 5 in cell D2 to a 3
worksheet routine highlights cell D2 with User#2's color, but doesn't block
the change.

Any help would be appreciated.

McBarker