Could not load type 'EPiServer.Web.InitializationModule' from assembly 'EPiServer'


After following al upgrade steps from upgrade from CMS 10 to CMS 11, but I keep getting the following exception on trying to access the CMS via the browser:

Could not load type 'EPiServer.Web.InitializationModule' from assembly 'EPiServer, Version=, Culture=neutral, PublicKeyToken=8fe83dea738b45b7'.

It seems that some code tries to load the type InitializationModule from the wrong assembly, as this specific type was moved from EpiServer.dll to EPiServer.Cms.AspNet, according to the upgrade documentation: EPiServer.Web.InitializationModule has been moved to EPiServer.Cms.AspNet assembly...

  • I have the correct 11.3.4 episerver DLLs in the /bin folder.
  • I have deleted any temporary files from c:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files\root\
  • I cleaned/rebuilt/restarted IIS

Still same issue.

Any ideas are welcome.


Feb 27, 2018 16:20

Do you have any 3rd parties assembly hanging around? They might be the culprit? 

Also make sure you have the correct binding redirect in web.config 

Edited, Feb 27, 2018 16:45
<p>I have viewed the assemblies being loaded using FusionLog, and indeed have seen that there are some custom Epi&nbsp;add-onns that were referencing an old Epi version These add-ons were&nbsp;POSSIBLE.RobotsTxtHandler and&nbsp;Geta.Tags. After updating both Nuget packages to their latest version the problem has disappeard (and replaced with another issue which I wont mention here.)</p> <p>Thanks for the help!</p>
Feb 28, 2018 8:46
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