Your ClickOnce clients complain of a missing “System.Data.Entity” reference in the GAC

So, Visual Studio 2008 SP1 came out the other day, and with it brought .net 3.5 SP1. I’ll leave you to read the shiny new features and what it brings from elsewhere. The purpose of this post is to deal with the failure to update or install certain ClickOnce applications.

With ClickOnce being a under-advertised feature of the .net framework, nobody really published a changelog of what’s new in it. I’ve managed to dig this up though, as it became quite necessary to fix the above error. So I’ll refer you to this link which contains some hints.

ClickOnce supports the following new features:

  • Suite Name: Your applications can now have sub folders on the start menu
  • Error URL: Not used this one specifically, but I’m guessing when something goes wrong during deployment your users can be directed to this URL
  • Creating Desktop Shortcuts: Fairly self explanatory
  • Excluding a file from having a hash generated: Means that this file won’t have it’s download verified
  • Clear Sign the package: Means that anyone will be able to update your app without having your private key (snk file)

So if you use any of those features, your users will require .net 3.5 sp1 installed on their computers. However, instead of prompting them with this useful message, they will receive an error telling them that System.Data.Entity cannot be found.

You can get round this by either not using the new features, or by marking .net 3.5 sp1 as a pre-requisite in your ClickOnce manifests

Published 12 August 2008 16:23 by Mat Steeples

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Comments

# Tip: System.Data.Entity and ClickOnce Deployment Issue@ 20 August 2008 20:59

I was developing a Windows forms application in .net framework 3.5, and I needed to include ClickOnce

Guillermo G. Blog

# re: Your ClickOnce clients complain of a missing “System.Data.Entity” reference in the GAC@ 12 November 2008 22:28

This article was really very useful. I was breaking my head with this message and found out that my client PC has .NET framework 3.5 and not .NET framework 3.5 SP1. Since I was using few of the latest changes found in 3.5SP1,

I was getting this message which really does not make since for the problem I was facing.

Thank you

Nalini

# re: Your ClickOnce clients complain of a missing “System.Data.Entity” reference in the GAC@ 31 March 2009 11:25

thank you

Andrija

# re: Your ClickOnce clients complain of a missing “System.Data.Entity” reference in the GAC@ 08 June 2009 21:55

Thanks for the tip. I knew that my latest change was a 3.5 SP1 (desktop shortcut) but didn't know what to do with this ugly error. All fixed now thanks to this article

Adam

# re: Your ClickOnce clients complain of a missing “System.Data.Entity” reference in the GAC@ 30 October 2009 10:52

Thank you for this information.

I just deployed a clickonce app and was getting this message when launching the app from one of my customers computers.

I marked 3.5SP1 as a requirement and everything is working fine now. Thanks! :-)

Steven

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