found a solution at https://askubuntu.com/a/1032156 and it works...
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1767276 Title: Could not delete variable: Interrupted system call (package shim- signed 1.34.9+13-0ubuntu2 failed to install/upgrade: installed shim- signed package post-installation script subprocess returned error exit status 1) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/shim-signed/+bug/1767276/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
