How to deal with "not installable" dependencies?

I ran sudo apt-get install -y unity-dictionary-lens and received a warning of unmet dependencies:

unity-dictionary-lens : Depends: unity-singlet (>= 0.2.0) but it is not installable

I found the package here but could not install it.

Solution 1:

Most probably, you haven't enabled the universe repository of Ubuntu, as unity-singlet is located there and not available in the main repository.

Check your settings in 'Software Sources' or modify you /etc/apt/sources.list accordingly in order to enable 'universe'.

Solution 2:

It should reference python-unity-singlet. I can fix that pretty easily, but it has some other problems, right now it doesn't work at all even if you can install it. In the future you should just file a bug about stuff like this. Here's the relevant bug for this one:

https://bugs.launchpad.net/onehundredscopes/+bug/1030284