According to the official list of known bugs of Visual Studio 2013 Preview this bug in maintaining the version of Entity Framework is not in the list. See the list here.
However, this may be an error not yet reported (officially). Actually there are still some errors regarding the use of EF in VS2013, as for some people there is no way to generate visual model sometimes. You can see the full list of related Visual Studio feedbacks (and bugs reported) with the Entity framework here.
A possible fix is to install the Entity Framework Tools for Visual Studio 2013 or the update of Visual Studio.
Here’s a question about how to force use EF4 in Visual Studio 2013... and, well, deleting dlls, using T4... can help you get around the problem right away: see question and answer here.
Good luck.
ATTENTION, ADDITIONAL IMPORTANT INFORMATION:
I’ve been tweeting with Julie Lerman and other fantastic people who work with Entity Framework when Jiri Waist sent us a link about this problem, read here.
I ended up forgetting this alternative, sorry, but it’s simple: install by Nuget the version 4 of the Entity Framework.
Visual Studio 2013 already comes with Nuget Console, you just need to go to it and enter the following code:
Install-Package EntityFramework -version 4.3.0
This will install version 4.3.0 in your project, if you want another version, just change 4.3.0 by the number you want.
This will surely solve your problem.
thanks for the links. About the American stackoverflow solution I think it’s not worth it, since the problem repeats with each update. If EF Tools upgrade does not work, I will continue using VS2012 for this.
– Cleiton
We’re here to help each other, Cleiton. It’s a shame nobody knows this bug. I talked to Julie Lerman and other beasts, and no one’s ever heard of that bug. If you allow me I would like to add this feedback to the official list.
– MayogaX