Multiplan (Microsoft Multiplan) - passwords - if you forget your password use a disk editor (Mac Tools, Mac Zap, Fedit), open the spreadsheet document, find block 3, part A, position 0079. If the spreadsheet is protected by a password, this location should contain a "1". Change it to 00 and
(save) write the changes back to the disk. Your spreadsheet should now be unprotected. Try this on a backup copy of your spreadsheet.