Hi,
I experience several issues after updating to calibre 6.1 - 64 bits no windows 10 :
1/ Kepub output extension does not work properly (Error "No module named 'PyQt4'"). This is now nicely solved thanks to davidfor's kepub output beta version (see this
thread)
2/ Calibre is unable to properly launch the E-book viewer when clicking on a book in calibre (details of the error log attached), although the E-book viewer is properly installed and running when launched directly from the installation folder.
(btw, I have uninstalled and re-installed Calibre, but this did not help, I also checked the path environment variable, which is correctly set to C:\Program Files\Calibre2\ ...)
Thank you for your help !