Hello. I am a recent convert to Linux running Mint 19.1 on an old Windows box.
I recently noticed that the Update Manager icon had a red cross in it and, when I opened it, I saw the following error message -
"Could not refresh the list of updates
Malformed entry 3 in list file/etc/apt/sources.list.d/additional repositories.list (Suite). The list of sources could not be read."
I found the offending file which contained three lines of which line 3 read -
I decided that I would try deleting the offending line 3 but, when I then tried to save the edited file, “I’m afraid that I can’t let you do that Dave”. My user account is an administrator but clearly I do not have enough privileges to change what looks like a system file.
I would greatly appreciate any help on how to resolve this problem.