why does undo feature not work after value entered?

[dachsieluvr]

In using a regular spreadsheet, that is not protected in Excel 2000, if an
error is made entering a value, formula etc in a cell, the Undo feature is
unavailable to reverse the entry. Why and how do I change it to have it
"reactivated"?

 

[Dave Peterson]

Do you have an event macro running?

If you do, this is common for macros to kill the edit|undo. The solution is to
turn off that event macro--but that kills what the developer intended.