Probably the error is due to the locked status of the cell linked to the
checkbox.
You are probably using the check box from the Developer Tab, in this case
you can find the linked cell by right clicking the control, select "Format
control" on the pop-up menu, and activate the tab "protection". Here there
is an option to unlock the control.
Then you should be able to protect the worksheet and use the check box.

"tgodrich" wrote:

When I protect my excel worksheet, my radio buttons and my check boxes are
protected and the form users cannot edit them. The properties are unlocked
for these controls, but that does not seem to have any effect. All other
fields in the worksheet that are not buttons or check boxes work correctly
and allow data entry.