Gaetan Bisson wrote: Users of the screen program will not be able to reattach older instances after upgrading to version 4.2.0; this is due to upstream having made a lot of changes to the internals, and switching from named pipes to sockets for communication. Please ensure your current screen instances are not anymore needed before upgrading. URL: https://www.archlinux.org/news/screen-420-cannot-reattach-older-instances/