[–] beetusvoater ago (edited ago)
No, I was mistaken. I only had the problem of not being able to add a new repo, which is really strange behaviour.
Anyway, you were right with your pinning hypothesis:
cat /etc/apt/preferences.d/*
Package: *
Pin: origin build.linuxmint.com
Pin-Priority: 700
Package: *
Pin: release o=LP-PPA-gwendal-lebihan-dev-cinnamon-nightly
Pin-Priority: 700
Package: *
Pin: origin download.virtualbox.org
Pin-Priority: 700
Package: *
Pin: release o=linuxmint
Pin-Priority: 700
Package: *
Pin: origin packages.linuxmint.com
Pin-Priority: 700
Package: *
Pin: release o=Ubuntu
Pin-Priority: 500
[–] ReverendJ1 [S] 0 points 1 point 1 point (+1|-0) ago
Weird. I've never ran into an issue adding a PPA. Some repos hosted elsewhere, yeah, but never a PPA from Launchpad.
Pretty interesting about the apt-pinning that Mint does, but like I said, it makes sense since it's using a base distro. I've just never seen it anywhere where it needed to be treated any differently than a regular Ubuntu box as far as adding repos goes though.