SQL Server Setup has encountered the following error: Mixed mode assembly is built against version 'v2.0.50727' I had SQL Server 2016 Standard Edition installed on a server. Due to some drive reconfiguration, I had to do a reinstallation. I uninstalled using the program and features and just as I was about to launch the setup to install it again, I went ahead and deleted the &quot;Microsoft SQL Server&quot; folder under &quot;Program files&quot;.
Most of the files were deleted and few remained, mainly in &quot;C:\Program Files\Microsoft SQL Server\130\Setup Bootstrap\SQLServer2016&quot;.
The problem is now when I am trying to launch the setup, it displays the error:

TITLE: SQL Server Setup failure.
SQL Server Setup has encountered the following error:
Mixed mode assembly is built against version 'v2.0.50727' of the runtime and cannot be loaded in the 4.0 runtime without additional configuration information.
Error code 0x84B10001.

Not sure how to proceed next.
Not a direct answer but some suggestion:

Use SQL Server Installation Center to start: System Configuration Checker. This tool will check for conditions that prevent a successful SQL server installation.



You can alterantivly:

1) Check setup log files at %programfiles%\Microsoft SQL Server\nnn\Setup Bootstrap\Log 

2) Check Your .net 4.0 installation and search your GAC for redundant dll files: