Please follow below mentioned steps:
Step 1:
Please enable Nuget Package Restore by right clicking on solution [as mentioned in below screenshot]
Step 2: [Follow this if the issue / error is not resolved by following step 1]
Still if you face the issue, please open .csproj file in notepad and check for the package path which might look like
So your solutions directory structure will be like:
\SolutionDirectory\
Package Directory:
\SolutionDirectory\packages
Project Directory:
\SolutionDirectory\ProjectName\ProjectName.csproj
Please open this .csproj [in which you’re getting error] in notepad and search for packages path and update it to its relevant path.
For e.g. my .csproj contained, if .csproj file contains ..\..\packages then update that path with ..\packages