Conflicting versions of detected ASP.NET web pages: the specified version is "1.0.0.0", but the version in bin is "2.0.0.0"

Question

This error appears after upgrading ASP.NET Web Assistant Library today to version 2.0, which apparently was released today. I updated by mistake, but would like to resolve it now, if possible.

Conflicting versions of detected ASP.NET web pages: the indicated version is "1.0.0.0", but the version in bin is "2.0.0.0". To continue, delete the files from the bin directory of the application or delete the version specification in web.config.

This seems to be a problem in web.config:

<add key="webpages:Version" value="1.0.0.0" /> 

Does anyone have any information on this ASP.NET Web Assistant 2.0 package? I could not find the release notes. Nothing on the Nuget site.

Answer 1

From Conflicting versions of ASP.NET web pages detected : You need to install the web pages: Version appSettings with the appropriate value. In your case, it should be 2.0.0.0

 <appSettings> <add key="webpages:Version" value="2.0.0.0"/> </appSettings> 

Answer 2

Something seems to be related to the new version (v.2.0) of Microsoft.Web.Helpers released on Jun / 05/2012.

To avoid this problem, I first uninstalled the new version (v.2.0):

PM> Uninstall-Package microsoft-web-helpers

And applied the following command to install a stable old version:

PM> Install-Package microsoft-web-helpers -Version 1.15

I believe (and wish) it will be fixed soon (or officially commented) ...

UPDATE

If for some reason you need an older System.Web.WebPages.dll (which in my case was overwritten by the new version and did not appear in the "Add Link" field), it is located at:

C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\Assemblies

Answer 3

You can refer to this question for help.

Unable to determine which version of ASP.NET web pages to use.

or you can read the instructions on the page

http://www.asp.net/mvc/overview/releases/how-to-upgrade-an-aspnet-mvc-4-and-web-api-project-to-aspnet-mvc-5-and-web- api-2