Working on this Excel workbook causes Excel to freeze for several seconds. Why?

"Have you tried simply copying the worksheets into a new spreadsheet?
This fixes many goofy Excel issues."

"Ensure empty rows and columns are really empty, by removing them once again. In old versions of Excel this will give you new empty rows and columns; in later version you might not see those.

To remove: right-click and select something like ""Delete Rows"". Do not press the Delete key, which would only delete the empty contents and does not help you.

To select: select the first empty row below the data, then hold down Shift, and press End followed by Down one or two times. Likewise: select the first empty column, keep Shift down, and press End followed by Right one or two times. (I am not 100% about the keys. You can also try Ctrl-Shift-End to extend the selection to the last cell in the sheet.)"