Time Machine and Volume backup issue after Sierra update I have updated to 10.12.5 yesterday and I am facing some issues with Time Machine and volumes where the backups are stored.
I used to have two Volumes where Time Machine backups are stored:


network volume
usb drive


The first problem I faced was that all the backups, either on network or on usb drive, stuck on "preparing backup" state.

I tried these solutions:


reset Time Machine (removing /Library/Preferences/com.apple.TimeMachine.plist
reset SMC and NVRAM


Nothing changed. Except for the fact that, since I reset Time Machine, my Volume with usb backup partition (HDMac) is not mountable anymore. Giving sudo lsof | grep disk2s2 I understood that system stuck on fsck_hfs. While backup on network drive is still on "preparing backup".

Can anybody help me?
The solution for my problem was simply waiting for some hours in order to obtain the backup. 

To repair my usb drive I ran fsck_hfs -fy /dev/disks2.