The source files could not be found.

I have several Windows 2012 VMs in a cloud environment and discovered I am unable to install certain roles / features. Attempting to do so fails with an "The source files could not be found." error. This somewhat misleading messages indicates Windows is looking for the OS install media. Most of the solutions on the Interwebz for working around this error describe how to set the server with an alternate path to the install media ... problem being that these VMs were created from a pre-activated OVF image and there is no install media available from the cloud's library.

Lacking install media the best solution is to set the server to skip the install media and grab the files from Windows Update.

1. Run "gpedit.msc"
2. "Local Computer Policy"
3. "Administrative Templates"
4. "System"
5. Enable "Specify settings for optional component installation and component repair"
6. Check the "Contact Windows Update directory to download repair content instead of Windows Server Update Services (WSUS)"

Due to technical limitations WSUS cannot be utilized for this purpose; which is sad given that there is a WSUS server sitting in the same cloud. :(