"Once I sorted the data, the original columns fell apart and error messages appeared, so I hit "Undo" a few times to restore their original forms in case I need the isolated data again (after the sorted data had been safely saved on another sheet)."
Hi cc,
Much easier to use a separate single column table in which to "paste formula results" for sorting.
Noted in my post last night:
"*Numbers does not sort single columns within a larger table. The 'single column' should be in its own one column table if you do not wish to change the order of other columns in the same table."
Using a separate table for the sort avoids any need for Undoing the effects of the sort on the main table.
Regards,
Barry