Hello! I just installed Linux Mint 18.1 KDE version. I think this problem might be still going on... Synaptic can not download all repository indexes. My error message:
The repository 'cdrom://Linux Mint 18.1 Serena - Release amd64 20170125 xenial Release' does not have a Release file
I tried changing the downloading mirrors, but I still get the error. Help please?