I have a file with multiple sheets, on one sheet I want each row to sum specific rows in a different sheet.
However, any time anyone filters either the source sheet or the output sheet all the sums break.

Also have tried turning the filters off, but the option is greyed out.

1. How do I reinstate the filter option in the toolbar so I can get rid of them? (and lock it again once I've removed)
2. How do I lock the calcs so they are unaffected by filters?

TIA