Protection is the difference between a workbook that survives and a workbook that breaks within a week. The senior uses Protect Sheet on every shippable workbook - the formulas are the value, the inputs are the user's data, and the structure is the architecture. Protection makes the workbook a deliverable, not a work-in-progress.
Protect Sheet
Review → Protect Sheet. The dialog has options for what the user can do when the sheet is protected - select locked cells, select unlocked cells, format cells, format columns, format rows, insert rows, delete rows, sort, use auto-filter, use pivot tables, edit objects, edit scenarios. The senior uses the default (select locked and unlocked) and adds specific permissions for the user. The pattern: unlock the input cells, lock everything else, set a password, share the password separately from the workbook.
Protect Workbook
Review → Protect Workbook. The dialog has options for Structure and Windows. The senior uses Structure - the user cannot add, delete, rename, or reorder sheets. Windows is for shared workbooks only. The pattern: protect the workbook structure so the tabs stay in the right order, with the right names, and the architecture is preserved.
Allow Users to Edit Ranges
Review → Allow Users to Edit Ranges. The senior uses this for any workbook where different teams have different access. The pattern: define a range for each team, assign a password, the team with the password can edit the range. The senior uses this on every multi-team deliverable - the inputs tab is editable by the data team, the calculations tab is read-only, the dashboard tab is editable by the partner.
The password discipline
The senior always sends the password via a separate channel from the workbook. The pattern: the workbook is sent by email, the password is sent by WhatsApp or SMS. The two channels make it harder for a bad actor to compromise both. The senior uses this for every client deliverable. The alternative - sending the password with the workbook - is the most common security mistake in any Excel engagement.
