System.runtime.handles and system.runtime.interopservices "requetsed 4.3.0 not resolved" error

I encountered lately 2 errors both related to 4.3.0 dependencies unresolved.

How do I resolve it ? (I have tried package manager uninstall and install again)

your help is much appreciated

You can download the packages using below URLs and add manually.

https://www.nuget.org/packages/System.Runtime.Handles/

https://www.nuget.org/packages/System.Runtime.InteropServices/

Thanks Sugumar8785 for the reply, I have downloaded the packages, when I use command at command prompt it returns :

Install-Package System.Runtime.Handles -Version 4.3.0
‘Install-Package’ is not recognized as an internal or external command,
operable program or batch file.

where can I find this “Install-Package” program ?

You have to import the package and install it. Follow below URL :

Thanks Sugamar Ramachandran for the reply,
I tried to comprehend the web link you provided, however failed to elicit needed instructions and steps needed to install the “Install-Package” exe, as I have already downloaded the System.Runtime.Handles 4.3.0, I guess it is the last step to get the Install-package.exe to run the installation, or may I wrong in my understanding, is not just 1 step away from manually installing the package ?