How to downgrade to an earlier release?

[chimak111]

...
If I download the 16.04 image and reinstall from a USB drive, will that overwrite 18.04 and bring me back to 16.04?

Give people here a chance to help you! Not everyone is in the same time zone. 18.04 is quite an improvement over 16.04.

[Snowhog]

For the moment, now that you are connected to the 'Net via a wired connection, you can now check for wifi drivers that might actually be available but not activated on your 18.04 installation. Go into Device Manager.

[jpc2769]

I'm not sure there is a process to "revert" to 16.04.

Do you have access at all to internet from this machine or any other? If so, see https://github.com/UbuntuForums/wireless-info right up to the end. If you post the information generated here or at ubuntuforums.org (in their networking & wireless subforum after reading the sticky there) someone may help you.

OK thanks, I have done this and will post in another thread.

If I download the 16.04 image and reinstall from a USB drive, will that overwrite 18.04 and bring me back to 16.04?

[jpc2769]

If you can, connect your PC to a wired network connection and then in a console, run: sudo apt update && sudo apt full-upgrade. Note any warnings and/or error messages reported.

OK I did that, here is what it says:

:~$ sudo apt update && sudo apt full-upgrade
Ign:1 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:2 http://archive.canonical.com bionic InRelease                                                                         
Hit:3 http://archive.ubuntu.com/ubuntu bionic InRelease                                                                     
Hit:4 http://ppa.launchpad.net/phoerious/keepassxc/ubuntu bionic InRelease                     
Hit:5 http://dl.google.com/linux/chrome/deb stable Release               
Get:6 http://archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]                           
Hit:7 http://ppa.launchpad.net/phoerious/keepassxc/ubuntu xenial InRelease                                     
Hit:8 http://ppa.launchpad.net/yubico/stable/ubuntu bionic InRelease                 
Hit:9 http://archive.ubuntu.com/ubuntu bionic-backports InRelease
Get:11 http://archive.ubuntu.com/ubuntu bionic-security InRelease [83.2 kB]
Get:12 http://archive.ubuntu.com/ubuntu bionic-updates/main Sources [159 kB]
Get:13 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages [304 kB]
Get:14 http://archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages [272 kB]
Get:15 http://archive.ubuntu.com/ubuntu bionic-updates/main Translation-en [114 kB]
Get:16 http://archive.ubuntu.com/ubuntu bionic-updates i386 Contents (deb) [6,148 kB]
Get:17 http://archive.ubuntu.com/ubuntu bionic-updates amd64 Contents (deb) [8,611 kB]
Get:18 http://archive.ubuntu.com/ubuntu bionic-updates/universe i386 Packages [173 kB]
Get:19 http://archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages [172 kB]
Get:20 http://archive.ubuntu.com/ubuntu bionic-security/main Sources [45.6 kB]
Get:21 http://archive.ubuntu.com/ubuntu bionic-security/main i386 Packages [128 kB]
Get:22 http://archive.ubuntu.com/ubuntu bionic-security/main amd64 Packages [159 kB]
Get:23 http://archive.ubuntu.com/ubuntu bionic-security/main Translation-en [60.9 kB]
Get:24 http://archive.ubuntu.com/ubuntu bionic-security i386 Contents (deb) [5,019 kB]
Get:25 http://archive.ubuntu.com/ubuntu bionic-security amd64 Contents (deb) [7,482 kB]
Fetched 29.0 MB in 8s (3,467 kB/s)                                                                                                                                        
Reading package lists... Done
Building dependency tree       
Reading state information... Done
All packages are up to date.
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following package was automatically installed and is no longer required:
 libzxcvbn0
Use 'sudo apt autoremove' to remove it.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Nothing looks out of the ordinary to me.

[Snowhog]

If you can, connect your PC to a wired network connection and then in a console, run: sudo apt update && sudo apt full-upgrade. Note any warnings and/or error messages reported.

[chimak111]

I'm not sure there is a process to "revert" to 16.04.

Do you have access at all to internet from this machine or any other? If so, see https://github.com/UbuntuForums/wireless-info right up to the end. If you post the information generated here or at ubuntuforums.org (in their networking & wireless subforum after reading the sticky there) someone may help you.

[jpc2769]

Yesterday I upgraded to 18.04.

So far, my wifi is completely broken, I have no audio, and I cannot use my yubikey to access my password database so I am locked out of email and everything else (which I need email to reset the passwords). Basically it has crippled my ability to work, and I am not sure I will be able to pay my bills without access to my bank accounts. I am sure there are plenty of other issues as well, I just haven't discovered them yet.

How can I revert to 16.04?