When it first occurred, I thought McCabe was lying and believe the same today. At the time there was internal debate as to whether McCabe should recuse himself from Clinton investigationss because of fire storm over alleged Clinton/McAuliffe pay offs through donations to his wife's campaign. But when Comey announced in late October 2016 that the FBI could not complete its review of the 650,000 emails before election day, McCabe rushed in and took over the document review (despite the recusal issue) and then promptly announced-review done, nothing there.
A detailed and sauced analysis of FBI inaction on the 650,00 Weiner laptop emails has been done by CTH: https://theconservativetreehouse.com/2018/04/28/fbi-never-investigated-abedin-clinton-laptop-emails-in-october-2016/