So all excited and hopeful you submit your app to the App Hub, thinking, “WOW, I am a real software designer now!” and then you get the message back:

xaperror

And then you Bing it, you google it (really, you really want google to know what you are doing?), And you find this blog.

Ha!

Ok, here is the fix (you will  have to scroll to see all of it):

In Expression Blend you will need to open your project with Visual Studio (FROM Expression, do not open the project directly with Visual Studio):

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Next in Visual Studio you will need to open the Project Properties (not the Solution Properties, if you have an older machine it might take a few seconds):

[Scroll down to see the next step]

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You will see the following, click on the button that says: Assembly Information (Continue to scroll down for complete solution):

 

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After clicking on the button you will see:

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Select English (if you are writing this in English) and not any of the other dialects of English, then click ok.

Build your application in Visual Studio, using Release and Windows Phone Device like the following:

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You new xap file is in the the same bin but a different folder.

 

That’s it, let me know if you need any other assistance by leaving a comment.

 

Build apps, lot’s of apps, make money.  As the saying goes: “Money might be dirty, but you can’t buy a washing machine without money.” (I just made that up.)