Comment # 4 on bug 1074160 from Cor Blom

(In reply to Ju_Ping Chan from comment #3)
> Is it possible that this problem is because of a difference between the
> repository version of calibre and upstream?

Upstream bug is probably still true:

https://bugs.launchpad.net/calibre/+bug/1441032

Try googling it. You cannot be the only one. Maybe someone has found a
workaround. I found:

https://www.mobileread.com/forums/showthread.php?t=244887

> Installing from the repositories yields a plugin error, so I stopped using
> it.

I don't get any errors, but you can try a bugreport.

I'm closing this bug, because it is not about our calibre.