Change File Associaton to Unknown File Type for .sdf file

[rov]

I am using Windows 10 64 bit.At first the .sdf was not associated to any file type association like notepad etc.It was coming look for an app in store.I accidentally clicked on a file type association now can't find a solution to change it back to the default one(i.e pick an app from store) and it shoul'nt be assocated to any type.I need this .sdf type to work on loadrunner tool.Please help

It should be like this

 

[pbcopter]

Hi and welcome.

See this tutorial

File Extension Type - Unassociate