No other ideas that are automated. To set it up with VBA you'd need to
determine the range of cells where comments are expected, and trigger
an event when one of those cells is changed. When that event triggers,
the code would insert the current date and time in the cell immediately
adjacent.

What is the tab name where the user is entering comments, and what is
the range of cells where this is likely to happen? It can be all of
column B, for instance, if that's the correct answer, just need to have
a range.

I have an answer for you, but it may take a while: I"m off to lunch and
then I have a series of meetings.