I faced this issue before during trying installing SharePoint 2013 prerequiests on a server that has .Netframework 4.6.1 installed . and I replacyed the
SVRSETUP.DLL file as mentioned at Microsoft support and the issue has been solved successfully.
But in your case, Framework 4.6.1 has been installed on a server that have already SharePoint installed.
So in this case, you need to do the following :
- Ensure you have rebooted since the installation of .NET 4.6.1 so that further management can occur.
- Stop all running services related to your product.
- Try to uninstall .Netframework 4.6.1 as mentioned here
- Run SharePoint configuration wizard on all sharepoint servers within the farm.
For more details check Uninstall .NET Framework 4.6.1 if you are installing older Microsoft Products - Exchange - SharePoint - Office Web Apps
Note: Regarding the Internal error when you tried to install Cumulative Update for Service Bus 1.0 (KB2799752), this is because of the service bus 1.0 maybe not installed.