Password protection gives your Microsoft Excel files security against unauthorized access, enabling you to provide copies of your documents to other people without giving them the ability to misappropriate your formulas or data. Unfortunately, if you lose your password, Excel's protections also can prevent you from using your own worksheets. Under specific circumstances, however, even protected files can yield up the information they contain, especially if you understand how Excel's passwords work and what they actually protect.
A password-protected Microsoft Excel document loses its password if the person who creates the file saves it to be compatible with the Excel 97-2003 format and doesn't reapply the password in an older edition of the program. Older versions of the software can't cope with the new password format introduced with Excel 2013, so they ignore its passwords altogether. If the file you're trying to use exists in a version compatible with an older version of Excel, open the document in that version of the software if you have access to a working copy.
Password protecting a Microsoft Excel workbook or worksheet and locking its cells constitute two separate steps. In a file that contains formulas you don't want others to see, extract and use but that rely on information that you need to change periodically, you can apply a password to keep prying eyes out of your file and unlock specific cells so you can enter weekly updates. After you enter the password to gain access to the file, you can copy or edit the contents of any cells that a document creator left unlocked.
The person who created and password protected the file you're trying to open can remove the password protection for you if she still knows the password she applied. Ask her to supply you with an open copy of the file or to give you the password itself. Unlike some applications that block your access to materials after a specific number of unsuccessful attempts, Microsoft Excel won't penalize you for trying, so if your friend or colleague seems uncertain of the proper password, you can enter each possibility that she suggests.
No Official Exceptions
Be careful with applying passwords. Unlike applications that apply password protection only after you save the file you want to encrypt, Microsoft Excel begins protecting a file the moment you tell it to do so, even if you've never saved the document in which you're working. In the classic example of this situation, you apply protection, go to lunch and return to make changes to your document, only to discover you can't remember the password you applied and thus can't work on the document. Microsoft can't help you defeat password protection, so calling for technical support won't reverse the process. You may be able to find a third-party application that claims to remove Excel's encryptions, but you risk data corruption and loss if you attempt these procedures.
Information in this article applies to Microsoft Excel 2013. It may differ slightly or significantly with other versions or products.
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