How to unlock a protected Excel sheet, and when no tool can help

The three kinds of Excel protection

Excel uses the word protect for three very different things, and knowing which one you are facing tells you whether this is a two-minute job or a lost cause.

Sheet protection (Review, Protect Sheet) stops people from editing locked cells, changing formatting or inserting rows on one sheet. The password is optional, and when there is one, Excel stores only a short checksum of it inside the file. The cell contents are stored in plain form; anyone can read them, and the lock only tells Excel to refuse edits.

Workbook structure protection (Review, Protect Workbook) stops people from adding, deleting, renaming or hiding sheets. Like sheet protection, it is a flag plus a checksum, and the data is fully readable. A related lock is the password to modify, which lets anyone open the file read-only but asks for a password to save changes.

The open password (File, Info, Protect Workbook, Encrypt with Password) is different in kind. Excel encrypts the whole file with AES, using a key derived from the password. Without the password the file is random bytes, and there is nothing in it to flip or strip. Everything in this guide about removing protection applies to the first two kinds, never to this one.

Unprotect a sheet or workbook when you know the password

When you have the password, the fix is a menu command. The steps are the same on Windows and Mac, and Excel for the web can unprotect sheets too. If the password is lost, skip to the next section or go straight to Unlock Excel.

To remove an open password you know, open the file, go to File, Info, Protect Workbook, Encrypt with Password, delete the dots in the box so it is empty, click OK and save. On Mac the same box is under File, Passwords.

1. Open the workbook and click the tab of the protected sheet.
2. On the Review tab, click Unprotect Sheet. If there is a password, type it and click OK. Locked cells become editable immediately.
3. For workbook structure, click Review, Protect Workbook (it shows as highlighted when active), enter the password, and the sheet tabs can be added or renamed again.
4. Save the file. Protection is part of the file, so an unsaved change is lost when you close it.

Remove sheet protection online from a file you can open

If the password is lost, or a former colleague protected a sheet and left, you can still remove sheet and workbook protection from any XLSX you are able to open. Unlock Excel removes the password, the sheet protection or the read-only mode from an XLSX you have the right to open. It is free, needs no sign-up, adds no watermark, and runs in the browser on a phone or computer. Files up to 300 MB are processed in memory and deleted after 30 minutes.

This works because of how the lock is stored. An XLSX is a ZIP of XML files, and sheet protection is a single element in the sheet's XML that says protected, with the checksum next to it. Removing that element removes the lock; your data, formulas and formatting were never encrypted to begin with. The same reasoning is why sheet protection should never be treated as a way to keep data secret.

1. Open Unlock Excel and add the XLSX file. It must be a file you can already open; an encrypted file that asks for a password at open time cannot be processed.
2. Run the tool and download the unlocked copy.
3. Open the copy in Excel. Review, Unprotect Sheet should no longer appear highlighted, and locked cells accept edits.

Why no tool can recover a forgotten open password

Since Excel 2007, a workbook encrypted with an open password uses AES encryption, and current versions use AES-256 with a key derived from the password through many thousands of hashing rounds. There is no master key, no backdoor and no flag to flip. The only approach is guessing passwords one after another, and each guess is deliberately slow. A short password made of a word and a year can fall in hours on a fast machine. A random twelve-character password would take longer than anyone will be alive.

That is why you should be wary of any website or program that promises to recover or remove any Excel password instantly. At best it strips sheet protection, the easy case above, and markets it as password recovery. At worst it is a vehicle for malware or a way to collect the files people upload. Honest recovery software runs a dictionary or brute-force attack, takes time, and succeeds only against weak passwords.

What to do when you forgot the open password

Before accepting that the data is gone, work through the places an unprotected or earlier copy might exist. Most forgotten-password stories end here, not with a cracking tool. If the file came by email, the password is often in a separate message or a chat thread. The version saved before the password was added is usually one folder away, and OneDrive and SharePoint keep earlier versions for weeks.

If none of that works and the password was weak, honest recovery software with a dictionary attack is the last option. If it was strong, the content is unreachable, and it is better to know that in an afternoon than after a week of waiting.

• Ask the author or sender; check the email or chat where the file arrived.
• Search Downloads, sent mail and shared drives for an earlier copy.
• OneDrive or SharePoint: right-click the file, Version history.
• Windows: Properties, Previous Versions. Mac: Time Machine.
• Check your password manager and try your usual patterns.
• Rebuild from the source data if the workbook was derived from it.

Is it legal to unlock an Excel file?

Removing protection from a file you created, own, or were given the right to edit is normal maintenance. Removing it from someone else's file to see or change what they locked is another matter. Depending on where you are and whose file it is, it can breach computer misuse laws, a confidentiality agreement, or an employment contract, and at work it can be a firing offense even when the data turns out to be harmless. This is a general note, not legal advice.

In a workplace, the right move when you inherit a locked sheet is to ask IT or the file's owner first. Most companies would rather hand over a password than discover that staff are stripping protection from finance files. Unlock Excel is built for files you have the right to open, and that is the only case this guide covers.

Read-only, Protected View and Mark as Final are not passwords

Several things look like a lock but need no password at all. A yellow bar saying Protected View appears on files downloaded from the internet or opened from email; click Enable Editing. A banner saying Marked as Final means the author flagged the file as finished; click Edit Anyway. A file opened read-only because someone else has it open on a shared drive, or because the file's Read-only attribute is set, can be saved under a new name with File, Save As. The same goes for a workbook with a password to modify: Save As under a new name gets you an editable copy. None of these protect the content, and none of them need a tool.

Protect the workbook properly afterwards

Once the sheet is open again, protect it in the way that matches your goal. If the goal is to stop people overwriting formulas, use sheet protection: unlock the input cells first (Ctrl+1, Protection, untick Locked), then Review, Protect Sheet. Know that this is a guard rail, not a lock, and anyone who wants to can remove it in a minute.

If the goal is confidentiality, set an open password. In Excel use File, Info, Protect Workbook, Encrypt with Password, or run the file through Password protect Excel, which puts an AES-256 password on an XLSX so the workbook only opens for people who know it. Choose a long passphrase, save it in a password manager, and send it to the recipient by a different channel than the file. Keep an unprotected copy somewhere only you can reach, because the section on forgotten passwords applies to you too.

If the sheet is damaged rather than locked, for example Excel reports the file as corrupted after an interrupted save, Repair Excel file rebuilds the XLSX and saves a clean copy.