So you've started your Windows 8 app development journey. All things are going smooth until one day you hit this error when trying to run/debug your app. The error says "Error: DEP0700: Registration of the app failed. An internal error occurred with error 0x80073D05. See http://go.microsoft.com/fwlink/?LinkId=235160 for help diagnosing app deployment issues. (0x80073cf6)"
This is a very cryptic error and does not give you any info about what the problem actually is. The problem is that Visual Studio is not able to delete the application data in your local packages folder.
Don't worry, the solution is actually very simple. On your Windows 8 machine, go to C:\Users\<UserName>\AppData\Local\Packages\ folder. There you will find a folder that has your application's Package Family Name in it - you just need to delete that folder. The issue is that while your app is in development, it might have a random GUID as its Package Family Name, so the folder will also have that random GUID as its name which makes it hard to know which folder belongs to your app. Again, that is easy to find as well. Right click your project in Visual Studio and click properties. The value you see in the "Package Family Name" field is the name you should look for in the folder. Simply delete it and build your solution again and it will run like a charm.
Read more details at http://paraswadehra.blogspot.com/2012/12/error-dep0700-registration-of-app.html