when selecting the "book" menu I get this message: Could not run script: BookModuleFactory.lua Error: Win32 API error 126
Which version of Lightroom are you using?
Looks like some important components of Lightroom are not installed properly on your computer.
Please reinstall Lightroom from your Installation media/Creative Cloud to resolve this issue
the version ist 6.2.1 automatically updated from the installfile Lightroom_6_LS11.exe which I still have.
Do I have to deinstall the current version first?