How to open the following register entry?

The key is "HKEY_USERS\S-1-5-21-1103555628-4237719376-2110276350-1000\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\MuiCache", I use the following code to open it but failed.

RegOpenKeyEx( HKEY_USERS,
        TEXT("S-1-5-21-1103555628-4237719376-2110276350-1000\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\MuiCache"), 
        0,
        KEY_ALL_ACCESS, //KEY_READ,
        &hTestKey);