VS2017 The operation failed as details for project could not be loaded

I've faced the problem several times, and all but one were solved by just closing and then restarting visual studio 2017. So if you've not, please try restarting VS, then if that fails, look for more serious solutions.

I've just had the same problem. Microsoft are apparently aware of the problem and have fixed in the preview of the next release, see the following comment for details:

https://developercommunity.visualstudio.com/comments/31393/view.html

In the meantime, the workaround is to open VS2017 (without loading your solution), open the Package Manager Console, wait for it to fully load, then open your solution.

I came across the same issue in VS 2017 with lastest .NET SDK updates. But here is a quick and easy fix that i was able to find.

While your project is open, open your 'Package Manager Console' and then run 'dotnet restore' command.

In the Package Manager Console window, make sure 'Package Source' dropdown on the top is set to 'All' and 'Default Project' is set to your project name

Just restarting Visual Studio 2017 can be enough to resolve this.