This policy setting controls whether Excel 2007 users can open Open XML files saved with pre-release versions of Excel 2007. Excel Open XML files usually have the following extensions: .xlsb, .xlsx, .xlsm, .xltx, .xltm, .xlam.
If you enable this policy setting, Excel 2007 users will not be able to open Open XML files created in pre-release versions of Excel 2007.
If you disable or do not configure this policy setting, users can open files that were saved in pre-release versions of the new Office Open XML format.
| Registry Hive | HKEY_CURRENT_USER |
| Registry Path | Software\Policies\Microsoft\Office\12.0\Excel\Security\FileOpenBlock |
| Value Name | Excel12BetaFiles |
| Value Type | REG_DWORD |
| Enabled Value | 1 |
| Disabled Value | 0 |