Known issues (from https://wiki.ubuntu.com/BionicBeaver/ReleaseNotes)

As is to be expected, with any release, there are some significant known bugs that users may run into with this release of Ubuntu 18.04. The ones we know about at this point (and some of the workarounds), are documented here so you don't need to spend time reporting these bugs again:

Desktop

- The computer suspends after 20 minutes of inactivity on battery power even if a user is logged in remotely. (GNOME:gnome-control-center#22)
- Bluetooth audio devices cannot be used in the Greeter. This will cause issues for people using the accessibility features such as screenreaders at the login screen. Once logged in everything should work as expected.

- Some admin utilities will not work with GNOME on Wayland since the apps have not been adapted to use PolicyKit to only use admin privileges for the specific functions needed. Also, some screenshot and screencast apps and all remote desktop server apps do not currently work on GNOME on Wayland. As a workaround, you can use the default Ubuntu session.

- Exiting the live session may get stuck with a "A start job is running for " error. You may need to forcefully power off the computer if you see this. (1706939)

- The Dock and Appindicator system extensions appear to be Off in tools like GNOME Tweaks. (They are on but cannot be disabled because they are system extensions for the Ubuntu session.) (1718850)

- Tracker is not installed by default. When installed, you must log out and log back in for the tracker service to start (1697769)

- Systems may fail to boot when connected over DisplayPort to an external screen, on NVidia graphics hardware such as the GTX970 chipset. (1723619)

- When an external monitor is connected to a laptop, the login screen is only displayed on the internal one and in some case is not visible (1723025)

- The warning dialog when a user force a UEFI installation does not respond to input event and the installation is then blocked at this stage (1724482) Avoid yourself some troubles and do not force a UEFI installation without a UEFI partition, grub-installer will fail anyway.

- Doing an "Entire disk" installation over an existing LVM installation will fail because the installer selects the wrong boot device (1724417) Use custom partitioning instead and manually select the right boot device in the combo box.

- The Files app remains at 3.26.

- Upgrading via the installer (Ubiquity) is deemed not safe due to bugs in apt-clone and so is no longer supported. (1756862) UIFE - remove ubiquity upgrade option.

- Setting a ulimit may cause segfaults in certain applications, especially those using webkit2gtk. Disabling the ulimit should restore normal functionality. More information in this Debian news entry: https://salsa.debian.org/webkit-team/webkit/blob/wk2/unstabl...

- Occasionally login may hang after an incorrect password (1766137). A workaround is to click cancel, click on your user and try again.

Server

- Partitioning step allows to configure LVM across multiple devices without requiring to setup a separate /boot partition. This may lead to failure to install the bootloader at the end of the installation, and failures to boot the resultant installations. (1680101)

- LVM configuration cannot be removed when volume groups with the same name are found during installation. Partitioner does not support installation when multiple conflicting/identical volume groups have been detected. For example reinstalling Ubuntu with LVM across multiple disk drives that had individual LVM installations of Ubuntu. As a workaround, please format disk drives prior to installation, or from the built in shell provided in the installer. (1679184)

- cio_ignore blacklist is no longer active after installation, because not all install-time parameters, like cio_ignore (s390x), are propagated to the installed system. Workaround is to edit /etc/zipl.conf to apply these and re-run sudo zipl to update the IPL. (1571561)