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excelregistryms-officeexcel-2013

Excel Does Not Prompt for Incorrect Extension (ExtensionHardening)

I have added the ExtensionHardening registry setting for the current user. Unfortunately, that setting isn't respected. When the user opens a spreadsheet, it doesn't prompt them about the format not matching the extension - It just doesn't open the file. Unfortunately, changing it so the files they are opening are in a matching format is not a viable option.

The user is on Excel 2013, and it was installed for "all users on this machine". This setting is not controlled by group policy for our intranet.

Here is the registry setting for a different version:

Key: HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Excel\Security Value: (DWORD)"ExtensionHardening" = [0 = Disable check; 1 = Enable check and prompt; 2 = Enable check, no prompt deny open] Default setting if value not present is 1 (enable and prompt).

(pulled from here)

My questions are:

  1. Is there something else I need to set?

  2. As a general question, how does "install for all users" vs "install for current user" affect the registry?

Solution

  • This was caused by the Excel 2013 Trust Center settings. There were several possible solutions:

    • Add the remote site to the set of trusted sites under Control Panel -> Internet Options -> Security -> Trusted Sites
    • Under Excel's options, choose "Trust Center", then selected "Protected View", and unselect the top option.
    • Right-click the file, select "Properties", choose "Unblock", and then click "Apply"