Q: Sierra and Time Machine

This is an update to my earlier post:

I have a slightly different experience.

In my case, as I posted a little earlier, ON/OFF of Sohpos affects the backup speed dramatically but is nothing to do with backup freezing (to be exact "endless preparing"). This is common to NAS HDD/direct-USB-connected HDD, and auto/manual kicking.

Once it is in the endless preparation, %CPU of backupd soars over 95% and the console is filled up with

default hh:mm:ss.ssssss +hhmm kernel AFP_VFS afpfs_vnop_ioctl:  afpfs_FindForkRef failed -1

, which I don't know the meaning.

ko

Almost all of my Sierra machines made in the meanwhile succesful Time Machine backups on different backup targets (Airport Extreme, Time Capsule, Netatalk TimeMachine Linux Server).

Only one machine ( an Early 2015, 13" MacBook Pro, i7, 16GB RAM on AirPort Extreme)  refused backups - by endless preparing backups.

Today I started a new try:

- stop the TM

- scrap the current backup

- restart the Airport Extreme

- mount the Backup-Volume

- add as a new TM-Volume

- start the Backup

- TM was asking to created a new backup

... after a while I got the message that the backup could not created but TM in the System preferences shows alway the preparing state and a small sparsebundle was build on the TM volume

Than I repeat the procedure as described before but befoire I start I added the mounted Backup-Volume to the privacy settings of Spotlight as described by some users here in the forum

- and ...

- ta da ... it started the backup after a few muinutes with an aacceptable performance

So in summary as I had also some troubles with on access scans of Sophos on other machines I guess there is a problem with the concurrent file access behavior of the TM daemons with other high performant access daemons like virus scanners or like here Spotlight

After having tried the other methods to no avail, I tried this, and it seems to be working. I started the backup process before leaving for work this morning (8 am) and when I got home at 6pm it said it was cleaning up old backups. Then about 6:30 it started backing up. But it's sloooow. It took one hour to back up the first GB. It's taken almost 2 hours to get close to the 2nd GB  - of 148.77 TB. This may take a while.

btw, no Sophos.

I'd wait for Apple to come up with a fix for this as it is obvious they have no clue what to do yet with it.  Don't be like me and go off of their advice to buy another external.  It's not the external drive, it's Apple's issues with their updates.  I have been backing up for the last 4 days and have only 138GB of the 938GB initial backup.  It is backing up but extremely slow.  And if it goes the way the other times have gone on my Time Capsule then it will cut out at halfway.  I still think this is Apple trying to get everyone over to the Cloud.  Just my assumption though I have received very angry feedback from fellow Apple peeps about even thinking about that conspiracy.  But I think they have taken the blue pill and believe that everything Apple does is perfect without possible agendas.  I love my Apples, don't get me wrong.  But this is a constant with them.  Do an update and screw up your new computer that once ran like a Ferrari.  Now, a Pinto. 

UPDATE: I just performed a manual backup of some 50-60GB. I haven't seen a failure message on my screen. This backup did however not update the date of my latest Time Capsule backup (ie, 21 September 2016). Nevertheless, the free available space on my Time Capsule has again decreased by some 50-60GB. This seems a weird contradiction.

Very happy it helped you!

I posted a set of steps given to me by a tier 2 support rep at Apple. Perhaps you can look at the post I've written to see if this helps you.

I'm using Sophos Anti-Virus Home Edition version 9.5.2 and followed your advice. Stopping the on-access scanner did the trick.

Thanks!

You are very welcome! Yes Time machine has been working like a champ since i ditched Sophos antivirus. After doing some reading i realised we don't need antivirus software anyway. or disk optimisers etc. ditch them all and run a nice clean system. Sierra running sweetly now.