I have a several class files. But Now I am added new model class and tried to type add-migration InitialCreate. But I am getting the following error.
PM> add-migration InitialCreate Exception calling "LoadFrom" with "1" argument(s): "Could not load file or assembly 'file:///C:\Users\user\Documents\Visual Studio 2013\Pro jects\DigitalHealthWebPrev\packages\EntityFramework.6.1.3\tools\EntityFramework.PowerShell.Utility.dll' or one of its dependencies. Operati on is not supported. (Exception from HRESULT: 0x80131515)" At C:\Users\user\Documents\Visual Studio 2013\Projects\DigitalHealthWebPrev\packages\EntityFramework.6.1.3\tools\EntityFramework.psm1:780 c har:62 + $utilityAssembly = [System.Reflection.Assembly]::LoadFrom <<<< ((Join-Path $ToolsPath EntityFramework.PowerShell.Utility.dll)) + CategoryInfo : NotSpecified: (:) , MethodInvocationException + FullyQualifiedErrorId : DotNetMethodException You cannot call a method on a null-valued expression. At C:\Users\user\Documents\Visual Studio 2013\Projects\DigitalHealthWebPrev\packages\EntityFramework.6.1.3\tools\EntityFramework.psm1:781 c har:50 + $dispatcher = $utilityAssembly.CreateInstance <<<< ( + CategoryInfo : InvalidOperation: (CreateInstance:String) , RuntimeException + FullyQualifiedErrorId : InvokeMethodOnNull Exception calling "CreateInstanceFrom" with "8" argument(s): "Could not load file or assembly 'file:///C:\Users\user\Documents\Visual Studi o 2013\Projects\DigitalHealthWebPrev\packages\EntityFramework.6.1.3\tools\EntityFramework.PowerShell.dll' or one of its dependencies. Opera tion is not supported. (Exception from HRESULT: 0x80131515)" At C:\Users\user\Documents\Visual Studio 2013\Projects\DigitalHealthWebPrev\packages\EntityFramework.6.1.3\tools\EntityFramework.psm1:809 c har:31 + $domain.CreateInstanceFrom <<<< ( + CategoryInfo : NotSpecified: (:) , MethodInvocationException + FullyQualifiedErrorId : DotNetMethodException PM>
Using the Package Manager, you need to re-install Entity Framework:
Uninstall-Package EntityFramework -Force
Then install it for each project:
Then do not forget to restart the studio.
I had a slightly different case today, I'm wirting the details here in case that might help somebody. The error was referencing one of my assemblies instead, on which the assembly containing the EF DbContext was depending.
I solved it setting the referenced assembly to "Copy Local" "true" so it'd make a local copy when building for migrations and therefore be able to find it.
Whats missing are the dlls from (Solution Folder)/packages/EntityFramework.6.1.3/tools/.
Things I would try:
If that doesnt work you can retry one of the above solutions of completely removing and reinstalling EF but make sure you install the same version for each project.
Also there seem to be versions that dont include those files. For example as of writing this answer 6.3.0 actually doesnt include the dlls needed while 6.1.3 does. I also had success copying the dlls from an older version like 6.1.3 into the newer like 6.3.1 (Might give a warning but generally works as expected).
I went to "Manage Nuget Packages for Solution..." and updated all my packages. This worked for me.
Then I got another error
Cannot bind argument to parameter 'Path' because it is null.
Setting another project as startup project other then my web app, before running any EF command in Package Manager Console, worked for me.
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