Hi,

Thanks for reaching out to us! After some research we found that after the update users saw "always use private browsing mode" enabled in FF. Disabling this allows ABP to run as normal. To do this, click the settings menu icon in the right corner of the browser > settings >privacy & security > scroll down to the history section > choose "Use custom settings for history" from the drop down menu > uncheck "always use private browsing mode". If you need more assistance please contact us via support@adblockplus.org.

Thanks
Shannon 
ABP Support Team