Calibre's loading just as quick as it always did for me - 1-2 secs max on an idle system for a 20,000+ book library.
I run 32bit Calibre on Win7 Pro 64bit with 6g memory and an i5.
I start Calibre in a specific view (View Manager), I don't show the 'splash' because there's never been a long delay. View Manager has an option to start Calibre in the 'where I was state' - trying turning it off.
I don't run Sigil often enough to know whether its changed
Maybe its the 'wireless tunnels breeding like rabbits' problem - see
https://www.mobileread.com/forums/sho...d.php?t=193686 The first glimmer of a solution, posted by Peter T, appears at post 50.
BR