How to protect a sheet with a password in Excel on Mac: steps for Microsoft 365

What sheet protection does and doesn't do

Sheet protection controls one worksheet at a time. It stops people from typing into cells you have locked. It does not lock the rest of the workbook, so other sheets stay open unless you protect them too.

Every cell in Excel starts out locked. That sounds strict, but the lock does nothing until the sheet is protected. Until then, the Locked box is just a setting. Protection is what enforces it.

Microsoft's Mac help article describes the job as two steps. First, clear Locked on the cells people may edit. Then protect the sheet from the Review tab. The article covers Excel for Microsoft 365 for Mac, Excel 2024 for Mac and Excel 2021 for Mac.

Choose which cells stay editable

Start with the cells, not the button. Ask who will open the file and what they need to change. Input cells and comment columns usually stay open. Totals, formulas and headers usually stay locked.

Take a monthly budget sheet as an example. The figures in columns B through E are typed in by hand. Column F adds each row with a formula. Clear Locked on B through E, leave F locked, and protect the sheet. Your team can enter numbers, and nobody overwrites a total by accident.

Two mistakes cause most of the trouble here. The first is protecting before you clear Locked. Then nobody can type anywhere, and people assume the file is broken. The second is clearing Locked on the whole sheet out of habit. That leaves formulas open to overwrites.

A quick check helps. Select a cell you plan to leave open, press ⌘1, and look at the Protection tab. If Locked is unticked, the cell stays open. If it is ticked, protection blocks edits there once the sheet is on.

Settings in the Protect Sheet dialog

The Protect Sheet dialog has a list called Allow users of this sheet to. Each tick is a permission. Anything you leave unticked is blocked after you protect the sheet. These are the options Microsoft's Mac article lists.

• Select locked cells: people can click cells you locked. They can see them but not change them.
• Select unlocked cells: people can click the cells you left open, which is where they type.
• Format cells, columns or rows: people can change formatting in those areas.
• Insert columns, rows or hyperlinks: people can add new rows, columns or links.
• Delete columns or rows: people can remove rows or columns.
• Sort and Filter: people can reorder data and use filters on the sheet.
• Use PivotTable reports: people can work with pivot tables on the sheet.
• Edit objects: people can change charts, shapes and other objects.
• Edit scenarios: people can change scenarios saved on the sheet.

Most shared sheets need Select locked cells and Select unlocked cells. Without them, people cannot click into the sheet at all. Tick Sort and Filter only if your team needs those tools on the protected sheet.

If the sheet holds a pivot table, check Use PivotTable reports before you protect. Without that tick, people may be blocked from working with the pivot table. For the pivot table steps, see how to make a pivot table in Excel on Mac.

Passwords are optional and not a lock on your data

The password is optional, and that choice matters. Microsoft's Mac article says that if you do not supply a password, any user can unprotect the sheet and change what was protected. A password stops casual edits. It does not stop someone set on getting past it.

The Mac article also says sheet protection does not stop malicious users. For that job, it recommends a workbook-level password. Microsoft's general protect article says the same thing in plainer words: worksheet protection isn't intended as a security feature.

Keep one rule in mind. Microsoft cannot retrieve a forgotten sheet password. If you lose it, the protected parts of the sheet can't be accessed. Store the password in a password manager on the day you set it, not later.

The 15-character password limit on Mac

Microsoft's Mac article sets a limit of 15 characters for passwords in Excel for Mac. Plan for it before you type anything. Pick a password you can remember or store in a password manager.

The same article covers the reverse problem. A workbook protected with a password longer than 15 characters in Windows Excel or Word can't be opened in Office for Mac. If your team moves files between systems, keep every password at 15 characters or fewer.

Microsoft's workbook password article does not mention the 15-character limit, so the two pages do not agree on paper. Before you rely on a longer password, test it on your own Mac, using a copy of the file.

Unprotect the sheet and change locked cells

Once a sheet is protected, the Review tab button reads Unprotect Sheet. Select the sheet, click Review, then click Unprotect Sheet. Enter the password if Excel asks for one. If you set no password, there is nothing to enter.

To change which cells are locked, unprotect the sheet first. Then select the cells, press ⌘1, clear Locked and click OK. Protect the sheet again from the Review tab. Microsoft's steps for editing locked cells follow this same order.

Excel for the web and Windows: what changes

Excel for the web uses a different path. Go to Review > Manage Protection, then turn on the Protect sheet toggle. Turning it off unprotects the sheet. A locked icon on the sheet tab means protection is on. Pause Protection and Resume Protection also sit under Review.

Password support on the web is less clear than on the Mac. Microsoft's general protect article describes a sheet password in the same Manage Protection pane. Check the current article before you promise a password to your team.

Windows wording differs too. Its dialog asks for a Password to unprotect sheet and then a Confirm Password box. The Mac dialog uses a Verify box. The Windows list also includes Use AutoFilter, where the Mac list shows Sort and Filter.

A worked example: a shared expense tracker

Say you run a shared expense tracker. Your team adds a date, a description and an amount for each purchase. A formula in the last column adds up each row. You want people to type in the first three columns and nothing else.

Here is the order that works. Select the three input columns, press ⌘1, clear Locked and click OK. Then go to Review > Protect Sheet, keep both select options ticked, add a password if the file leaves your team, and click OK.

Test before you send the file. Type into one open cell, then into a formula cell. Excel should accept the first entry and refuse the second. If it accepts both, the sheet is not protected yet, so go back to the Review tab.

Common mistakes that cause trouble

• Protecting before clearing Locked. Nobody can type anywhere. Unprotect, clear Locked on the input cells, and protect again.
• Forgetting the password. Microsoft cannot retrieve it, and the protected parts stay inaccessible.
• Treating the password as security. Without one, any user can unprotect the sheet.
• Typing a password over 15 characters on Mac. Excel for Mac limits sheet passwords to 15 characters.
• Protecting one sheet and assuming the workbook is locked. Protection applies to each sheet on its own.
• Leaving formulas in unlocked cells. Anyone who can type there can overwrite the formula.

Next steps: protect the whole workbook

If the file leaves your team, protect the whole workbook too. Microsoft's article Require a password to open or modify a workbook covers that. It says that if you lose the password, you can't open or gain access to the workbook, so write the password down and keep it safe.

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