Originally Posted by Mamaijee
I have ticked on comments but still they do not show up !!!!!!!
Try going to Preferences - Miscellaeous - Open calibre configuration directory.
1 - Now exit calibre.
2 - Rename the configuration directory to Calibre Settings.old or something similar in case you decide to go back to it.
3 - Start calibre
A new configuration directory will be created and you may have to point calibre to your library again. This will remove all custom settings but may fix your problem.