If the .VMDF file is known to your system, it is possible to open it by double clicking the mouse or pressing ENTER. This operation will start applications associated with the .VMDF file installed on your system. If the system encounters a file for the first time and there are no relevant associations, the action will end with a system’s proposal to find the appropriate software on your computer or in the Internet.
Sometimes it happens that the files of the .VMDF type a wrong program is assigned. This can sometimes be the result of the action of hostile programs such as viruses and malware, but most often it is the result of an incorrect association of an application with the .VMDF file extension. If, during the operation of a new type of .VMDF files, we will indicate to the system a wrong program, the system will erroneously suggest its use every time it encounters this type of file. In this case, try to re-select the appropriate application. Right-click on the .VMDF file, and then select from the menu the option
"Open With ..." and
"Choose default program" . Now select one of the installed application from the list above and try again.
If our system cannot cope with the .VMDF extension and all the automatic and semi-automatic methods to teach it have failed, we can only manually edit the Windows registry. This register stores all information about the operation of your operating system, including file extension associations with programs to support them. The REGEDIT entered in the window "search for programs and files" or "run" for older versions of the operating system, gives the access to the registry of the operating system. All operations performed in the registry (even those little complicated for the .VMDF file extension) have a significant impact on the operation of our system, therefore, before any modifications, make sure that you have a copy of the current registry. The section important for us is the key HKEY_CLASSES_ROOT . This manual shows step by step how to modify the registry, specifically the entry in the registry that contains information about .VMDF file.