I have faced a problem with net-Framework-core package installation. As you probably know, this package is deprecated, but still available, when you specify source. It can be installed by command
Add-WindowsFeature net-Framework-core -Sources <path to Windows Server 2012 installation media>\Sources\SxS
If that doesnt work, you should check several things:
- Is the installation media from the same build as current OS (should be)
- Isnt it corrupted
- Sometimes it is helpful to map installation media on another server and use UNC path instead of local
- In my case problem was in Windows Update Services setting. The registry key stated, no automatic update is possible and WUS is used for updates.
Solution: Locate registry key below, change value to “0” and install net Framework core feature. After done, change back to “1” – if still no go, change value to 0 and reboot server prior to install.