So, I have a monolithic development farm (DC, SQL Server, SharePoint 2016) all in one VM that I use to develop solutions for SharePoint. I had Visual Studio 2015 installed, but my coworkers wanted to start using Visual Studio 2017.
As you probably know, when you uninstall Visual Studio, it doesn't uninstall all of the stuff that comes along with it. So I removed all of the packages installed on the same date as Visual Studio 2015. The only thing is, I uninstalled WCF Data Services as well (v 5.6.0.0). I don't know why it wasn't listed on the day I installed SharePoint, maybe it was, and maybe I was a bit aggressive.
Well it turns out that CSOM requests (Microsoft.SharePoint.Client.ServerRuntime) and it is dependent on Microsoft.Data.Edm and Microsoft.Data.OData (both v 5.6.0). These are both prerequisites for SharePoint 2016, but don't show up as a problem when just accessing the site. Here's the PowerShell code that would trigger the issue:
# $ctx is a valid, initialized ClientContext
$ctx.Load($ctx.Web)
$ctx.ExecuteQuery() # throws a 400 Bad Request exception
I first found the problem by trying to access the site via CSOM. Then I upgraded to a newer CU and PSCONFIG.exe failed. Checking the PSCONFIG.exe log I found I had the same problem. That lead me to this support post SharePoint 2016 Configuration failed, and it set me on the track to solve the issue.
I first tried to replace the individual packages, but that didn't work very well (I couldn't seem to download the right packages). So I re-ran the SharePoint prerequisite installer and that was the key to success.
Here's some of the errors from various logs that lead me to the solution. Maybe by posting these errors, it will draw people to this page if they come across a 400 Bad Request error from CSOM code.
From the Upgrade log:
Exception: Could not load file or assembly 'Microsoft.Data.Edm, Version=5.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
Exception: Could not load file or assembly 'Microsoft.Data.OData, Version=5.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
From the ULS Logs:
Error when processing types in server stub DLL Microsoft.SharePoint.Client.ServerRuntime, Version=16.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c, Error=System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information. at System.Reflection.RuntimeModule.GetTypes(RuntimeModule module) at System.Reflection.Assembly.GetTypes() at Microsoft.SharePoint.Client.ProxyMap.ProcessOneAssembly(Assembly azzembly, ClientServiceHost processorSurrogate) at Microsoft.SharePoint.Client.ProxyMap.Init(ClientServiceHost processorSurrogate)
System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Data.Edm, Version=5.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified. File name: 'Microsoft.Data.Edm, Version=5.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'
System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Data.OData, Version=5.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified. File name: 'Microsoft.Data.OData, Version=5.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'
