Thanks. I deleted 3 of the worksheets and then deleted all of the
columns/rows not used in the remaining one.
File size is 640kb. I then copied that worksheet over 3 times to
restore the data and file size is about 2.4 mb. This is unusual, on
my other workbooks with the same data the file size with 21 worksheets
is 1.8 mb.

There is nothing pointing to data outside the worksheet or any charts/
graphs or the like. The total data is less than 300 characters + two
buttons with very small macros. Curiously every time I key in data it
pauses with the hourglass.