Comment 3 for bug 927274

I ran into this issue with a different package by performing the following steps:

1) Launch update-manager
2) Check for updates (There must be updates available)
3) Click on settings
4) Switch to the "Ubuntu Software" tab
5) Choose a different server in "Download from: "
6) Click "Choose server"
7) Authenticate
8) Click "Close"
9) update-manager will now crash as it tries to look up one of the packages that used to be in the cache.

Additionally, the crash won't be reportable because apport thinks it is not an official package as apt-cache policy shows the following:

9:47:51 - flash:[...ch/bug-attachments/plymouth] apt-cache policy update-manager
update-manager:
  Installed: 1:0.156.5
  Candidate: 1:0.156.5
  Version table:
 *** 1:0.156.5 0
        100 /var/lib/dpkg/status