Time Machine in Sierra messed up again!

Here are instructions on how to reinstall usb fax modem support on Mac OS Sierra. They simply involve copying a few files from a previous El Capitan install. It works on my system, and the working fix is persistent after the 10.12.3 upgrade.

I filed a bug report and was told that Sierra supports multi-function printer faxing, but not "legacy" fax modems.

Personally, I have no interest in adding more peripheral clutter when all I need is a sub-$15 modem and a phone cord, especially when the fix is copying over a few files.

If dropping support for fax modems affects you negatively, please take the time to issue feedback at Apple's website, https://www.apple.com/feedback/macosx.html.

There are many many many threads about this. It is a Sierra issue. I have a MBP running Sierra and its backup to TM fails EVERY MONTH.

It is not the HDD, as I have a MacMini running El Capitan that backs up to the same TM and has been for YEARS.

Only the Sierra Mac fails. every month.

Wow so I'm not alone with the TM backup issues since upgrade to Sierra! Especially the fact that it fails exactly every month for me as well. Does about 3-4 weeks worth of backups no issue and then get the verification fail where it needs to start all over again. I know I did not have this issue with El Cap so it was definitely introduced with Sierra. Wonder what triggers in the OS or TM application every month that could be causing this fail for us.

funny you should mention something like this. I have an old mac air and when an update on yosemite, I ended up in kernal task call ****. So I had yosemite reinstalled (I had heard horror stories about el capitan updates so I went backwards)

popped in a new backup disc for time machine, with the knowlege that no matter what I could restore it to factory since I had the initial backup after the reinstall. Well after a year or so, the kernal task call mess started up again, so I used the time machine to reinstall from the earliest backup. I moved my tools to another machine and decided I would only use the air to surf the net, since if I downloaded something evil, so what, I could always restore the machine.

Well today, the kernal task interupts were in the 10k to 100k range and the air ran like a dog. I go back to restore to the factory setting and guess what: All my backups from and entire year were gone, INCLUDING the factory backup. The time machine wiped me, and I am left with a deranged kernal task caller dog slow machine, with nothing left to fix it.

So the time machine erased a huge section of my backup disc. How clever of apple.. (#!$#@#$!#@#@!@!)

Please refer to macOS Sierra: If you see a message that you must create a new backup.

I'll answer the easy one first:

-- is there any way to scan the backup drive to see what TM is unhappy with?

Yes.

Hold an Option key while selecting the Time Machine icon in your Mac's menu bar, and select Verify Backups.

-- is there any way to fix the current backup so TM is happy to continue using it?

No.

When Time Machine detects corruption, it locks down the last intact backup making it "read only". That ensures it will be preserved, as if in amber. You can be reasonably assured it's intact. TM is very conservative that way.

Anticipating your next question, why did this happen. When a TC internal hard disk fails (not if but when), it's most likely to fail following a lot of read / write activity – exactly the kind of activity that a major macOS upgrade will cause. Although Apple uses "server grade" hard disk drives in TC, they have a finite lifespan just like any other. You can erase the internal hard disk and it might continue to work, or it might not. You said you already has that sort of failure in the past, so that was a clear warning of what was to come. In any event you should no longer consider that TC a reliable backup destination, and either replace it (or its internal hard disk drive, which can be done, with difficulty). You can use Time Machine's Archive function to copy its contents to another TC or external USB HD.

Causes other than a definitely failed hard disk are possible. Those causes are often attributable to poor power quality or network communication failures. You can address the first one by using a quality UPS from a reputable manufacturer. Considering you are using Ethernet, the second is much less likely to be the case in your installation, but if you are using any intervening switches or connections, inspect them.

You can use the following shell script to extract Time Machine log entries created within the past 48 hours:

clear; printf '\e[3J' && log show --predicate 'subsystem == "com.apple.TimeMachine"' --info --last 48h | grep -F 'eMac' | grep -Fv 'etat' | awk -F']' '{print substr($0,1,19), $NF}'

It will record various errors and failures but most of them will be inconsequential even when everything is working normally. I do not believe it will identify anything actionable, but you are welcome to try it and post its results if you like. If you do, please omit or obscure anything you don't want to appear on a public and searchable website.

Also, if I copy and save the current TM sparsebundle (this is the read-only image, I hope), is there then a way to point TM at it as the source to display the contents within the "Enter Time Machine" display?

Yes. You will be using the same Option key function as before, and select "Browse Other Backup Disks..."

Hi, since installing Sierra every backup has failed. I have checked the HDD, including deleting and recreating a partition. Time Machine still fails. The HDD is fine; I have successfully copied significant files to it with no problems when testing it.

At the moment Sierra seems to be a significant step backwards!

I have a Mac Mini Server Mid 2011 2Ghz i7, 16GB RAM, connected to a 12TB RAID via Thunderbolt. I also have a 12TB WD MyBook Duo (firmware updated) that has been the drive Time Machine backed up to. After upgrading to Sierra (currently 10.12.1) Time Machine got stuck in the Preparing Backup loop. I tried patience, but after a week I decided to reformat the backup drive and try again. No luck. Ran DiskWarrior and rebuilt the directories. Nothing. Reformatted again. For some reason it worked that time. It took a week to backup the RAID the first time. Then it seemed to be working normally. For two days. This morning it was back to "Preparing Backup". But only for about an hour, then it just stopped trying and said it will make another attempt in half an hour.

For the record, no antivirus software. The only thing running is the server software (ver. 5.2) and the only thing that does is grant access to the users. No services (mail, calendar, etc.) are running.

... but if the alternative is to erase all my backups to date, figure it's worth a try, especially since the disk repair process worked.

It is not possible to "repair" hard disk drives in the sense that you imply. A hard disk drive that has experienced corruption sufficient to be detected by Time Machine or Disk Utility should be considered sacrificial unless and until its underlying cause is positively identified and corrected. Those failures are not even reported to the host until the drive's firmware gives up on attempting to correct the read/write failure, presumably after multiple attempts.

Unless and until that cause is positively identified and corrected, it will remain and is 100% certain to result in another failure. You can certainly experiment with a hard disk that has failed, and I encourage you to do so, as long as you understand that device can no longer be considered a reliable backup option.

I provided two such likely reasons for those failures, but they are uncommon compared to simple hard disk drive failure due to age, environmental factors, mechanical damage and similarly mundane reasons.

Thanks for the link but I cannot seriously consider any reference containing as many grammatical errors as that one. Its author also seems to have overlooked Apple's published requirements for Time Machine backup devices. Details matter.

To add to my previous post, the backup just completed (4 days in the making), but upon finishing it stated there are "no current backups" and that the next backup will take place in one hour. Even curiouser (to paraphrase Louis Carroll, as I feel I'm slipping down the rabbit hole) I can enter Time Machine and see the current backup, all glorious 5.6TB of it, but if I look at the drive itself through the finder all I see is the "2016-11-02-114002.inProgress" file, again all 5.6TB. Previous attempts that ended this way never recovered to begin the next backup and my only recourse has been reformat and try again. I am stumped.

My problems started when I installed Siera, Canon printer errors, usb fax modem and Time Machine. Last week I reinstalled El Capitan, which was a fun process, and the problems disappeared. Having then again installed Siera on a clean HDD the problems are back.

Apple fixed the Canon printer error through a Siera update. Hopefully, Apple will identify and correct the Time Machine problem through an imminent software update.

It is claimed that Apple has dropped support for fax users using USB fax modems; I cannot comment on other fax solutions. I cannot be the only user irritated by the 'big brother' attitude of Apple in removing a useful means of communication without consultation. Hopefully, Apple will listen to its customers and reinstate fax support as, but I will not hold my breath!