I too have this issue with third-party .deb files. I have just installed 16.04 in UEFI with / and /home on their own partitions.
When I booted, I updated my box and was able to install Slack using the Software Center. After that, I went to install Chrome and it wouldn't work. Now, no third-party .deb files will install through the software center. I am able to install any default package from the Ubuntu Software Center but I am not able to install any .deb files unless I manually install them using: `sudo dpkg -i PATH_TO_DEB_FILE.deb` I have fully updated my system after a fresh install. I ran: ``` sudo apt update Ign:1 http://dl.google.com/linux/chrome/deb stable InRelease Hit:2 http://dl.google.com/linux/chrome/deb stable Release Hit:4 http://us.archive.ubuntu.com/ubuntu xenial InRelease Get:5 http://us.archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB] Get:6 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB] Get:7 http://us.archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB] Fetched 306 kB in 0s (542 kB/s) Reading package lists... Done Building dependency tree Reading state information... Done All packages are up to date. ``` ``` sudo apt upgrade Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. ``` ``` sudo apt dist-upgrade Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. ``` This issue still persists. At this point, I can only install manually. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1672424 Title: Cannot install Debian files outside of the repositories To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-release-notes/+bug/1672424/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs