Q:

Kentico error The file '/CMSModules/Chat/Controls/SupportChatHeader.ascx' does not exist

I'm trying to setup a development machine for upgrading Kentico 11 to 12. Version 11 is under TFS source control and packages are not added to source control.
On dev machine I used NuGet to add Kentico.Libraries and Kentico.Libraries.Web.UI  packages.
The solution on dev machine is compiling, but I'm getting this runtime error when I try to browse to Kentico CMS
The file '/CMSModules/Chat/Controls/SupportChatHeader.ascx' does not exist

A:

My assumption is that the missing files been removed or were not added to TFS, which would go some way to explain their absence.  If you have other functioning environments (UAT or perhaps production), then I would think about copying the files back from them to update the local environment.
I have had a similar issue once before, but we found that the upgrade replaced the missing files for us, so it may be worth just giving the upgrade a shot.

