I was in the middle of upgrading from 12.04 to 14.04 when my internet service went down. The upgrade aborted. On switching to another network and trying sudo do-release-upgrade -d, I get the following output and error:
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [198 B]
Get:2 Upgrade tool [1,148 kB]
Fetched 1,148 kB in 0s (0 B/s)
authenticate 'trusty.tar.gz' against 'trusty.tar.gz.gpg'
exception from gpg: GnuPG exited non-zero, with code 1
Debug information:
gpg: Signature made Sat 12 Apr 2014 11:55:14 PM EAT using DSA key ID ********
gpg: /tmp/update-manager-QyUNc1/trustdb.gpg: trustdb created
gpg: BAD signature from "Ubuntu Archive Automatic Signing Key <[email protected]>"
Authentication failed
Authenticating the upgrade failed. There may be a problem with the network or with the server.
What is causing this and how can I fix it?
The solution is to switch back to the original network. The upgrade resumes on trying the command. Perhaps the key is network/IP specific.