This error occurs when the local datastore has become corrupted. To re-create the datastore, you should delete the datastore and reopen a solution by the following the steps.

Caution:
This process deletes any custom items that you have added to your datastore, such as devices copied from an existing device, emulator configuration properties, and so on.
To delete your datastore and reopen the solution

Save your work, and then close all remote tools and Visual Studio.

Delete all of the contents of the Corecon directory.

This directory is located under %LOCALAPPDATA%MicrosoftCoreCon.

For example, del %LOCALAPPDATA%MicrosoftCoreCon1.0*

Restart Visual Studio.

A new datastore has been created.