Excel macros that protect and unprotect worksheets may run slowly

Symptoms

Macros in Microsoft Excel 2013 run slower than in earlier versions of Excel. For example, you may notice that .xlsm files open very slowly or that it takes a long time to move to the next cell when you enter data in cells.

Cause

Because of a new, stronger hashing algorithm (SHA-512) for encryption in Microsoft Office 2013, macros that protect worksheets and unprotect worksheets run slower if they protect or unprotect several worksheets sequentially.

Resolution

This behavior is by design. It's not noticeable when you’re manually protecting a worksheet. However, if you have code that protects or unprotects work sheets repeatedly, this behavior can cause a performance issue. This is a known issue and is documented at the following Microsoft Office website: 

More Information

The delay is caused by a stronger hashing algorithm (SHA-512) than is present in earlier versions. (The default hashing algorithm to protect files by requiring a password in Office 2010 is SHA1.) This change can cause a performance issue for some Office developers.  

For more information about worksheet protection, click the following article number to view the article in the Microsoft Knowledge Base:  
822924  Description of Office features that are intended to enable collaboration and that are not intended to increase security  
Properties

Article ID: 2996166 - Last Review: 27 Aug 2014 - Revision: 1

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