I was thinking that it might be more useful to BR or chaley actually, since they know more about library structure than I do. I was unclear.
That said, I did download it and try it in my Win10 Cal5.38 64bit on an SSD. Switching between VL or directly between VM views with this (nearly) empty test library is basically instant for me.
jnikkir's CPU (reported earlier) is a 2017 model according to google, that shouldn't be old enough to make
that much difference. Not unless win11 on that hardware is a slug. I remember past windows 'upgrades' that made older hardware basically unusable.
If it were me, I'd try reinstalling Calibre (and making sure you have 64bit) and rebooting the computer if you haven't already. Not because I have a reason, just because it's a reflex.
