After installing Calibre, I immediately changed the preferences particularly by enabling system tray icon. The program restarted, as required, but the icon didn't appear on my sys tray. So I tried restarting my laptop, but still the same negative result. I have already whitelisted all apps after installing my OS so the problem is likely not that.

Is there another solution for this?

I'm using 12.04 64-bit on my ThinkPad R61i.