[projectorlochsa]

Nope. Works slow with 0 books, although I do have about 700, which still is by Big-Oh standards, at least it should be, small.

[michaelmrose]

2422 books here all of the above ought to be small though as noted. I think it would be interesting to profile and figure out which part is slow. Is it equally slow if you run calibredb add in the terminal?