Since upgrading to Firefox 40 the Adblock filters do not load on start up and can take up to 10minutes to reload.
I manually add a subscription EVERY time I start Firefox.. Not the end of the world but a nuisance..
Firefox 40 - Adblock S...L...O...W to respond
Re: Firefox 40 - Adblock S...L...O...W to respond
strange, you could reset firefox, reinstall ABP