Editor’s note: In the video, Brandon Vigliarolo walks you through the steps of securing an Excel workbook with a password in Microsoft Office 365. The steps are similar to what Susan Harkins describes in this tutorial, which was first published in January 2011 and updated in March 2019.

Securing data is a tiered process with password protection at the bottom level–the file level. It’s a first step effort, but certainly not the only step you should take to protect confidential and proprietary data. Password protecting an Excel workbook at the file level controls access in two ways: It lets a user in, and it lets a user save changes. In this article, I’ll show you more than just how to password-protect a workbook. You’ll learn what that protection does and doesn’t do for you and how to avoid some gotchas.

I’m using Office 365 Excel (desktop), but you can user earlier versions. There’s no demonstration file–you won’t need one. You can’t add a password to a file open in the browser, nor can you open it in the browser.

Security v. protection

Before we discuss Excel’s password-protection feature, let’s clarify what we mean by security. Although the terms security and protection are bantered about interchangeably, feature-wise in Excel, they aren’t the same thing. Security lets you choose who gets in and by virtue of doing so, who doesn’t. Protection limits users who are already in. Security is about access; protection is about maintaining integrity.

Assign the password

The first step is to assign a password. You can work with any file, but for our purposes, I suggest a blank workbook instead of an important working file, just in case. To assign a password to an Excel workbook, do the following.

  1. From the File menu, choose Save As. In Excel 2007, click the Office button and choose Save As.
  2. Under the name and type controls, click More options. (If you’ve suppressed the Backstage area, you’ll skip this step.)
  3. In the resulting Save As dialog, click the Tools dropdown (to the left of the Save button) and choose General Options.
  4. In the resulting dialog (Figure A) you can set two passwords: One to open the workbook and one to modify the workbook. Advanced options let you set encryption options.
  5. Enter one or both passwords and click OK.
  6. Confirm the password(s) and click OK.
  7. Click Save.

Be sure to note the password somewhere safe, just in case you forget it.

Figure A

Enter the password and note it in a secure place.

Setting a password to open the workbook is self-explanatory; if a user doesn’t know the password, he or she can’t open the file. That gives you a great deal of control if you do a reasonable job of securing passwords. Of course, you can’t really do anything about the user who shares a password, but that’s an altogether different problem. Just remember that this password only keeps users out; a user that knows this password has access to all the data and can modify the data once in.

SEE: Cost comparison calculator: G Suite vs. Office 365 (Tech Pro Research)

That’s where the second password comes in; by assigning this password, you allow users to open the workbook and view the data while withholding permission to modify anything. A user who knows this password can view and modify data and also save changes to the workbook.

A user who doesn’t know the second password can open and view the data by clicking the Read Only option, but it’s Read-Only–sort of. This user can still modify data, but the password-protected workbook won’t let the user save changes–sort of. Here’s the deal: A user without the modifying password can still view, modify, and save changes, if the user can get in. This user just can’t save the changes to the protected workbook. The user can, however, save the protected workbook using a new name, which certainly circumvents the process.

SEE: A winning strategy for cybersecurity (ZDNet special report) | Download the report as a PDF (TechRepublic)

Important considerations

Before you start password protecting all your workbooks, there are three important things to keep in mind:

  • Anyone with the password to modify the workbook can also remove the password protection. Use this particular option wisely; be careful who you give the password to.
  • Casual users won’t have the expertise to crack your password, but anybody can purchase password-cracking software. Your best protection against this type of tampering (or outright theft) is to assign a ridiculously long password of random characters. Doing so won’t defeat specialized software, but it will slow it down and that delay might cause the would-be cracker to put your workbook aside. On the other hand, it’s sure to annoy your users. Balancing the two needs can be a bit of a high-wire act. For more on this subject, read Strong passwords–realistic or burdensome.
  • If you forget your password, you can’t get into your workbook and make changes, but you can purchase the password-cracking software.

Excel’s password protection is a great feature and fortunately, it’s easy to implement. Just don’t confuse it with sheet protection and by all means, don’t rely solely on it to secure sensitive data.

SEE: 10 Excel time-savers you might not know about (free PDF download) (TechRepublic)

Send me your question about Office

I answer readers’ questions when I can, but there’s no guarantee. Don’t send files unless requested; initial requests for help that arrive with attached files will be deleted unread. You can send screenshots of your data to help clarify your question. When contacting me, be as specific as possible. For example, “Please troubleshoot my workbook and fix what’s wrong” probably won’t get a response, but “Can you tell me why this formula isn’t returning the expected results?” might. Please mention the app and version that you’re using. I’m not reimbursed by TechRepublic for my time or expertise when helping readers, nor do I ask for a fee from readers I help. You can contact me at susansalesharkins@gmail.com.

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