The (hkcr.exe) HKEY_CLASSES_ROOT key is one of the vital section in the Windows registry, and this particular key looks after all of the file extensions that we have in Windows.
Steps to find hkcr.exe
1. Click Start and type regedit in the ‘Search programs and files text box and press enter.
2. If you are asked for user access control then click yes.
3. Registry Editor opens. The First one, HKEY_CLASSES_ROOT is the hkcr.exe.
The HKEY_CLASSES_ROOT (HKCR) contains file name extension associations and COM class registration information such as ProgIDs, CLSIDs, and IIDs. It is primarily intended for compatibility with the registry in 16-bit Windows.
The Windows registry is the backbone to any Microsoft based operating system and of this registry, you will find several registry keys. Registry keys are used to divide the various data entries in to specific categories that can be accessed by the user, or more readily by other software.