Try the following  (Copy and pasted from another post reply) 

If its just locally you want to get this to work and not fussed about the visitor groups, than try the following  

• Run Stored Procedure BigTableDeleteAll
• Delete the Contents in : VW_VisitorGroup 

If you are inclided to find which Visitor group you might be missing you can look up in the View VW_VisitorGroup and map what you have setup in codebase. 

When we did the upgrade from 11 to 12 at the time we found Episerver.Forms.Samples was not upgraded theirfor missing some visitor groups. 

Hope this helps 

Thanks Minesh, and sorry for the late reply. I've not dared to run BigTableDeleteAll yet as there is a lot of other stuff in that table. We have a backup of the original database, but we did a lot of manual tweaks during the upgrade and I'm afraid it will take us some time to get everything up and running again if we need to start from scratch. I will probably try what you suggest, but after we have discovered/estimated all/most other "challenges" we have with the upgrade to CMS 12 (and they are plenty).

I think you need to just update namespace to he new name as they changed namespaces

If you have custom visitor group criterion defined in code, then there are a couple things to keep in ming when upgrading to cms 12 :

1. If you've refactored code that resuted in change of assembly name or namespace on these, you will most likely need to revert that, as that won't match up to whats saved on cms 11 database.
2. There have been changes to property attributes, where DojoWidget attribute is now obsolete and you should instead use CriterionPropertyEditor attribute instead. The save logic has also changes, so ensure to have both getters and setters on your model properties. More details here.

As for categories, if you have custom categories in code, you will need to give them a Guid that matches your cms 11 database, or else the code will create new ones, and because the same name already exists in DB, it will append a (1) to the new one's name and that won't match your conditions in code and result in runtime errors.

Thank you Mark and Ritu! We have some custom logic for visitor groups that might need to be updated, but no custom categories or similar, so otherwise I cross my fingers and hope that a namespace update is all that is needed. 😬

We had a similar issue after upgrading to CMS 12. We noticed the error below in the logs which was due to the use of the 'User Profile' criterion in the CMS 11 site. 

2023-10-30T02:46:20.314688657Z fail: EPiServer.Personalization.VisitorGroups.VisitorGroupRole[0]
2023-10-30T02:46:20.314901362Z       Unable load criterion of type 'EPiServer.Personalization.VisitorGroups.Criteria.UserProfileCriterion, EPiServer.Cms.AspNet'
2023-10-30T02:46:20.315123367Z       System.IO.FileNotFoundException: Could not load file or assembly 'EPiServer.Cms.AspNet, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.

Every visitor group that used the old AspNet 'User Profile' criterion had to be manually updated in the CMS to use the new version. Editing the Visitor Group in the CMS reveals the same error.

User Profile now lives in Site Criteria.

I hope this helps fellow upgraders 😃