How to avoid Excel from prompting "The file you are trying to open, , is in a different format than specified by the file extension"? (转)

ID: 3ACF4AF056A7790848257AD400279396
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1. Launch Windows Registry Editor (Windows Start button -> Run... -> type: regedit)

2. Navigate to the "HKEY_CURRENT_USERSoftwareMicrosoftOffice[OfficeVersionNumber]ExcelSecurity" key, where [OfficeVersionNumber] has to be matched with the version number of your installed MS Office.

[OfficeVersionNumber]
Office 2003 -> 11.0
Office 2007 -> 12.0
Office 2010 -> 14.0
Office 2013 -> 15.0

3. Insert a new DWORD value:
- Value name: ExtensionHardening
- Value type: REG_DWORD
- Value data: 0

4. Navigate to the "HKEY_USERS.DEFAULTSoftwareMicrosoftOffice[OfficeVersionNumber]ExcelSecurity" key, where [OfficeVersionNumber] has to be matched with the version number of your installed MS Office.

5. Insert a new DWORD value:
- Value name: ExtensionHardening
- Value type: REG_DWORD
- Value data: 0