When I try running the command "update-database", I get this exception:
Specify the '-Verbose' flag to view the SQL statements being applied to the target database. System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. File name: 'Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
WRN: Assembly binding logging is turned OFF. To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1. Note: There is some performance penalty associated with assembly bind failure logging. To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].
Could not load file or assembly 'Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.`
I believe I had the same issue as you did. I didn't save the whole error message, but my error message was
'Could not load file or assembly 'Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.'
I am using Visual Studio 2017 and was trying to do Update-Database after Add-Migration.
To resolve the issue I closed Visual Studio and re-opened it, then re-ran Update-Database again.
This may or may not resolve your issue, but I thought I'd post just in case it would help.