[c#] Could not load file or assembly 'Microsoft.Web.Infrastructure,

In some cases cleaning the project/solution, physically removing bin/ and obj/ and rebuilding would resolve such errors. This could happen when, for example, some packages and references being installed/added and then removed, leaving some artifacts behind.

It happened to me with Microsoft.Web.Infrastructure: initially, the project didn't require that assembly. After some experiments, the net effect of which was supposed to be zero at the end, I got this exception. Above steps resolved it without the need to install unused dependency.