Could not load file or assembly System, Version=2.0.5.0 in .NET 4 MVC 4 application

Question

Been searching for ages, can\'t find anything helpful. Here is the exception I\'m getting:

Could not load file or assembly \'System, Version=2.0.5.0, Culture         


        

Answer 1

I just want to share another solution from here that solved the problem on my development machine: installing Silverlight 5 SDK (only 11.2MB at the time of writing this post) was enough to make everything working.

Answer 2

Starting from a machine configuration that only had VS2017 and Silverlight 5 SDK on it, I installed VS2015 on top of that. This is when I started getting the System.Core and System.Windows problems.

When I uninstalled VS2015 and re-installed Silverlight 5 SDK, these problems went away.

Answer 3

Edit the web.config file to remove the reference, which is not required for normal operation:

1 - Open the web.config file in the root of your site

2 - Find the following line and comment it out():xxxxx-is your assembly name.

<add assembly="xxxxx", Version=2.0.5.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

3 - Save and close the web.config file and try again

Answer 4

Make sure your .NET framework is patched. Microsoft released patches to .NET to allow Portable Class Libraries to properly find the appropriate runtime (KB2468871). If you are seeing the above exception (or something like it), it means you're missing the latest .NET framework patches.

Answer 5

I found that it was the "await" and "async" that where giving me trouble.

I had Windows XP SP3 with only .NET 4.0, but had to update it to .NET 4.0.3 using KB2600211 - this wasn't updated automatically through Windows Update when .NET 4.0.3 came out because the computer is off-grid.

This is the link to the update:

https://www.microsoft.com/en-us/download/details.aspx?id=29053

Answer 6

Install Microsoft® Silverlight® 5 SDK from the following link. It resolves and works fine for me.

SDK download