Open the Tools menu and select Protection, Protect and Share Workbook. The Protect Shared Workbook dialog box opens.
Click the Sharing with Track Changes check box to select it; this activates Excel's Track Changes feature and prevents others from turning off the feature.
To require people to enter a password to access your worksheet, type the password you want to use in the Password (Optional) text box and click OK.
The Confirm Password dialog box opens. Type the password you typed in step 3 and click OK. Excel notifies you that the workbook will be saved; click OK.
INTRODUCTION
If you share your workbooks with other users, you might want to protect your workbooks by restricting access to them and tracking changes made to them. Don't forget the passwords you assign to your workbooks; otherwise, you won't be able to access them!
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File-sharing Options
Excel offers two other file-sharing options. Protect Sheet allows you to protect the contents and objects in a worksheet. Protect Workbook allows you to protect the structure and windows in a workbook.
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Unprotecting a Workbook
To remove the protection from a workbook, open the Tools menu and select Protection, Unprotect Shared Workbook to open the Unprotect Sharing dialog box. Enter the correct password and click the OK button.
