Kontact needs both akonadi and nepomuk to run. When akonadi is not running, Kontact offers to start it (or starts it automatically). However, if nepomuk is not running, Kontact does not try to start it. As a result, several features are disabled. The only fix seems to be to use nepomukctl, which is probably a solution only for a minority of informed users.

Obviously, these two cases are not strictly equivalent since Kontact cannot run without akonadi, whereas it can run, albeit with reduced functionality, without nepomuk. However, it would be nice if Kontact could automatically start nepomuk when available. [As a side note, the difference between the two dependencies (akonadi vs nepomuk) is one of code rather than usage, i.e. while a developer would understand why Kontact currently automatically starts akonadi but not nepomuk, this may not be clear for an end user].

Reproducible: Always

Steps to Reproduce:
One use case that I am familiar with (but there may be others) is the following:
1. ssh to a remote host.
2. start Kontact.
3. akonadi is automatically started, but not nepomuk.
Actual Results:  
Nepomuk is not started.

Expected Results:  
Nepomuk is started (if available, of course).