Specify Unknown File Type Options (All Windows)

These settings allow you to specify a description and the application to launch to view files with an unknown extension.

1.Open your registry and find the key below.
2.Set the "(Default)" value to equal the description you want to use for unknown file types.
3.Create a new sub-key called [HKEY_CLASSES_ROOT\Unknown\shell\Open\Command] and set the "(Default)" value to equal the command used to view unknown file types. Substitute the symbol "%1" to represent the filename in the command (e.g. "notepad.exe %1").

Restart Windows for the change to take effect.

Registry Settings
System Key : [HKEY_CLASSES_ROOT\Unknown]
Value Name : (Default)
Data Type : REG_SZ (String Value)

Disclaimer : Modifying the registry can cause serious problems that may require you to reinstall your operating system. We cannot guarantee that problems resulting from modifications to the registry can be solved. Use the information provided at your own risk.