I tried updating Ubuntu 12.04 by following the guide at http://www.ubuntu.com/download/desktop/upgrade but I received this error message:
What do I do?
Either you get the keys or you just disable the ppa for the upgrade to 12.04/10.
to disable the ppa open up the "software sources", which you will find with the unity dash, and uncheck spotify's repository in "Other Software".
after this is done, try the system upgrade again using the "Update Manager" which also can be found in the dash
If you want to get the new public key for spotify instead, you have to open a terminal and use these 2 commands
gpg --keyserver subkeys.pgp.net --recv-key 94558F59
gpg --export 94558F59 | sudo apt-key add -
after you successfully executed these commands try the upgrade again.
