Policy
Force file extension to match file type
Microsoft Office
Policy overview
Key metadata and intent for this policy.
This policy setting controls how Excel loads file types that do not match their extension. Excel can load files with extensions that do not match the files' type. For example, if a comma-separated values (CSV) file named example.csv is renamed example.xls (or any other file extension supported by Excel 2003 and earlier only), Excel can properly load it as a CSV file. If you enable this policy setting, you can choose from three options for working with files that have non-matching extensions: - Allow different - Excel opens the files properly without warning users that the files have non-matching extensions. If users subsequently edit and save the files, Excel preserves both the true, underlying file format and the incorrect file extension. - Allow different, but warn - Excel opens the files properly, but warns users about the file type mismatch. This option is the default configuration in Excel. - Always match file type - Excel does not open any files that have non-matching extensions. If you disable or do not configure this policy setting, if users attempt to open files with the wrong extension, Excel opens the file and displays a warning that the file type is not what Excel expected.
Registry values
How enabled and disabled states update the registry.
No explicit registry values are set for enabled or disabled states.
Policy elements
Inputs and configuration options exposed by this policy.
| Scope | Element | Type | Registry mapping | Constraints & behavior | Copy |
|---|---|---|---|---|---|
| User | L_Empty ID L_Empty | enum | Path software\policies\microsoft\office\16.0\excel\security Value name extensionhardening Type REG_DWORD | Options: Allow different (0), Allow different, but warn (1), Always match file type (2) |