I don't know what the problem is, but if it's any comfort, mine has started doing the same thing since the last update. Mind you, yours does take considerably longer than mine (approx 5 minutes for a 200 Gb disk).
This thread is now locked and can not be replied to.
Sniper Elite 4 review: Headshotting Nazis has never felt so good
1995-2015: How technology has changed the world in 20 years
The Fresh New Fonts of 2017
WWDC 2017 dates: How to get WWDC 2017 tickets, when is WWDC 2017 and more details announced
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.