How to I automate setting acrobat not to ask if you want it to be set as the default?

Acrobat standard and pro 2015 are asking if I want them to be the default every time I launch the program.  How do I automate setting this to no so my users will never get prompted?  I know I can manually set it in options but I do not want me users to have to do this.  Is there a reg key I can populate to prevent it from asking?