I have a large workbook with lots of macros that has worked well for a
couple years. Suddenly, any text or number I type or copy into any cell
within a certain column repeats itself to as many repetitions as is
viewable, depending on the column width. So if the column is wide enough to
show three characters and I type CAT, but then drag the column wider, I
would get CATCAT, then CATCATCAT, etc. The cell edit box only shows CAT, and
math still works OK, so it may be more of a view or display problem than a
cell contents problem. I read about using an asterisk as a repetition
initiator when using a custom cell format, but these cells just have a
general format. Maybe there is some setting I have accidentally initiated,
or maybe my macros are rebelling.

Sorry if I'm the 99th person to ask about this, but it has me stumped.
Thanks.
Carl