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macOS 10.13 High Sierra Now Available: When Should You Upgrade?

Apple has now released macOS 10.13 High Sierra via the Mac App Store for Macs running at least OS X 10.8 Mountain Lion, going back to the MacBook and iMac from late 2009 and the MacBook Air, MacBook Pro, Mac mini, and Mac Pro from 2010. (These are the same hardware requirements as for 10.12 Sierra.) As we noted at the very start of our WWDC coverage in “Tripping to macOS 10.13 High Sierra” (5 June 2017), High Sierra is one of Apple’s smaller upgrades in the recent “tick, tock” of operating systems, including Leopard/Snow Leopard, Lion/Mountain Lion, Yosemite/El Capitan, and now Sierra/High Sierra.

However, as much as High Sierra has relatively few user-facing changes and new features, Apple is using the release to make some huge updates under the hood. High Sierra automatically converts Macs with SSDs to the new APFS file system (see “What Apple’s Forthcoming APFS File System Means to You,” 24 June 2016) and uses the new HEVC and HEIF formats for videos and photos (see “HEVC and HEIF Will Make Video and Photos More Efficient,” 30 June 2017). These infrastructural changes should modernize the Mac’s underpinnings, improve performance, reduce storage needs, and pave the way for future improvements.

The significance of those changes raises the question: when should you upgrade your Mac to High Sierra? With iOS, and even more so with watchOS and tvOS, we generally trust Apple enough to upgrade quickly, in large part because the company exercises such control over those operating systems that they can’t vary much. Plus, frankly, problems with an Apple Watch or Apple TV aren’t likely to impact your life much.

On a Mac, though, there are innumerable opportunities to stray from the straight and narrow, and many users do. If developers follow Apple’s rules, and if Apple did its due diligence during beta testing, there should be no problem with upgrading to High Sierra. But there’s no way to know if the hardware and software on your Mac meet Apple’s specs, or if Apple was able to test your particular configuration. That doesn’t mean anyone failed to do their jobs right; it’s just a fact. Add that to the fact that many of us rely heavily on our Macs to get our jobs done, and the upgrade question becomes all the more important.

Happily, if you follow Joe Kissell’s advice in “Take Control of Upgrading to High Sierra” and make a bootable duplicate right before upgrading, you have nothing to lose except perhaps time. That’s because, in the worst case scenario, you can always reformat your Mac’s boot drive and restore from your bootable duplicate. Joe has released the 1.1 version of his book now, and it includes instructions for downgrading if necessary.

That said, there’s no harm in waiting, and High Sierra doesn’t have so many features as to make the upgrade immediately compelling (for an in-depth guide to what’s new, and much more, see Scholle McFarland’s “Take Control of High Sierra”). If you fall into one of three main groups of users, we recommend holding off on High Sierra for at least a few weeks, or until 10.13.1 comes out with the usual bevy of bug fixes:

  • If you can’t spare the time to deal with unanticipated problems. That’s true if you’re upgrading your own Mac or if you’re upgrading the Macs of users who you support (see “Important High Sierra Changes for IT Admins,” 11 September 2017).

  • If you’re uncomfortable with the tasks involved with downgrading despite Joe’s advice.

  • If some piece of software you rely on is incompatible with High Sierra. Developers are releasing updates, but older versions of apps may experience problems.

Users of one particular class of software should delay upgrades: those who rely on disk utilities that haven’t yet been upgraded to be compatible with APFS. You really don’t want to let an old disk utility touch an APFS-formatted drive. That could also be true of backup software. Although the developers of Carbon Copy Cloner and Mac Backup Guru have said that they’re ready for APFS, the developers behind SuperDuper have expressed more worry due to minimal documentation from Apple (nonetheless, SuperDuper 3.0B1 is available for testing).

If you do upgrade to High Sierra, make sure to maintain a Time Machine backup, since Apple has undoubtedly used its internal knowledge about APFS to update Time Machine as necessary. Up-to-date backups protect you from a multitude of evils.

Now, despite these words of caution, if you’ll excuse me, I need to finish going through Joe’s checklists so I can upgrade my main iMac.


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Comments about macOS 10.13 High Sierra Now Available: When Should You Upgrade?
(Comments are closed.)

Jeff Hecht  2017-09-25 16:44
What about those of us who have home or office networks with some machines that can't run 10.13 because of hardware or software issues? Can macs running 10.11 or 10.12 access files in APFS formats on other Macs in the network?
Mike Vlasman  An apple icon for a TidBITS Contributor 2017-09-25 17:10
Hi Jeff,

I just tested by networking my iMac (10.12) to my MBA (10.13) and everything is there and accessible.
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-25 17:23
That shouldn't be a problem, except for the fact that Macs whose drives are formatted with APFS cannot use AFP for networking and must rely instead on SMB. Since SMB has been the default for a while, few people should have any issues there, even still.
Jeff Hecht  2017-09-26 13:11
I'm afraid "should" is the appropriate word. A while back I ran into a problem with file sharing between my MacMini and MacBookPro, both running El Capitan. I couldn't share files either way until I turned off SMB in the file-sharing preferences. This is discussed in but you have to ignore the first proposed solution, which does not work for most and should not have been flagged as "solved". There may be some other root problem, but I spent quite a while finding this work-around.
nick304  2017-09-25 17:41
Any comments on whether the problems with PDFKit in Sierra have been fixed in High Sierra? I have not seen any update yet on this issue which is definitely still a concern for many.
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-25 18:00
I haven't heard anything yet, but I'll ping my sources.
For me, there are more problems with pdf than ever ! Pdfkit is so bad I think downgrade to Sierra
Did the download, then install and reboot. Now for the past 2+ hours have nothing but white screen with a circle and slash. Have tried SafeBoot, but it won’t go there for me. Found this website while seeking help.
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-25 18:00
Sounds like it might be worth restoring from the backup you hopefully made right before updating.
Those of us who ditched stuff like CCC and SD years ago in favor of the built-in Disk Utility for cloning/restoring can rest assured that our workflow will remain fully compatible with APFS and/or macOS X HS.
Problem is, Apple's backup not bootable. And that's a requirement for me...I have software which runs 24*7 and need to get back up and running quickly. I'll sort out the problem on the primary boot drive later.
TM Backups aren't bootable. Clones made with Disk Utility are very much bootable considering they're a bit copy.
Doug Lerner  2017-09-25 20:08
I read an article that said that APFS only worked on SSD right now and was wondering how this would work with my Carbon Copy Cloner and TimeMachine HDD drives.

But I also saw an Apple page on this saying that bootable HDD would work with AFS - is that the same as APFS?

So my MBP is SSD, and my two backup drives are HDD. Am I safe in that regard?
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-26 09:44
High Sierra automatically converts your Mac's boot drive to APFS if it's an SSD, and you can't avoid that. If the boot drive is a Fusion Drive or hard disk drive, it will not be converted. High Sierra will not convert any external drives automatically, regardless of type.
B. Jefferson Le Blanc  2017-09-26 19:19
You can choose to convert an HDD or a Fusion Drive to APFS, but it's not required in order to run High Sierra.

Apple seems to use AFS in some of their articles when they are talking about APFS. This is certainly confusing and, in my opinion, quite careless in an environment where precision is important. The file system Apple has been using for many years is HFS+. APFS (or AFS) is new. Supposedly it's more efficient, but that premise has not been well tested yet. If you upgrade to macOS 10.13 your SSD will be converted to APSF automatically. You don't say what utility you used to create your backups. Until whatever utility you used is upgraded for High Sierra you will not be able to use them for further backups. But, as Adam suggests, you should be able to boot from those backups in order to reformat your SSD to HFS+ and then you can clone the backup to your internal drive. If you have no problems with High Sierra on your SSD then this will not be necessary. But it's important to be prepared for trouble rather than wish you had.

It's also important to repeat the advice to bring your backup up-to-date just before you upgrade to High Sierra, just in case you need to downgrade.

I make a point to hold off upgrading my system until I've heard from early adopters (like Adam) how well or poorly the new system works. Almost without exception it does no harm to wait. In the present case there are a number of changes in the technologies under the hood in High Sierra that have not really been tested "in the wild." I've got more reading to do before I'll be confident that I understand them sufficiently well.
Doug Lerner  2017-09-26 19:24
As a test, I upgraded my "just for emergencies if my MBP is broken" iMac late 2009 to High Sierra. No problems so far, but it took a very long time. I started it at about midnight, and at 2 am it was still showing "20 minutes left." This morning it was done and I had the login screen.

Now it's going through something, I don't know what, with iCloud. In the meanwhile, the other settings and apps are working.

System Utilities shows the HDD was not converted to APFS automatically. I suppose there is some way to do that?

My backup utility is the latest version of Carbon Copy Cloner, which is supposed to be High Sierra ready.

When Apple mentions AFS they mean Apple File Service as opposed to let's say SMB. AFS has nothing to do with APFS. The former is a protocol for file sharing (remember AppleTalk?) while the latter is a file system.
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-27 10:31
Usually I see AFP (Apple Filing Protocol) instead of AFS. Technically, AFP is part of AFS, I guess...
Oh yeah. I believe it's at least as common to see AFP as AFS. I believe the former is just part of the latter (one of the protocols offered), but it's the part users probably deal with most, especially considering the historic evolution of file sharing on the Mac.
Josh Centers  An apple icon for a TidBITS Staffer 2017-09-27 12:08
Please disregard this comment. This was true in beta but not true in the release version. Apple says APFS is coming to Fusion Drives, but hasn't given a firm timeline.
One thing that is definitely wrong in 10.13 is the Safari. The Activity Monitor reports Safari or the network content process (Not responding). Try the news web pages and hangs.
As a comment. If you come across speed problem with the Safari check extensions. I got rid of one at it now works very fast.
Dr. Greg A Steinke  An apple icon for a TidBITS Contributor 2017-09-25 22:36
Any comment about upgrading when one has an iMac fusion drive?
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-26 09:42
You can upgrade to High Sierra, but your drive won't be converted to APFS. I imagine that at some point during the evolution of High Sierra that will happen, much as it did with iOS in 10.3. So I don't have a feel for whether you'd prefer to wait until Fusion Drives are supported for APFS, or if it's better that they'll remain as HFS+ right now.
John Baxter  An apple icon for a Friend of TidBITS 2017-09-27 19:59
I'm sure posts and articles will appear about how to convert the Fusion drive boot portion to APFS. I recommend staying away from those (as I plan to) until Apple releases a dot release that does that job.

I have a slightly odd situation in that I just bought an (Apple refurbished") Mini 2014 with fusion drive. Since I was phasing over from an old iMac which is stuck on El Capitan, I went onto the public beta soon after lighting up the machine (but late enough that the drive was not converted, saving the "unconvert.") That meant I could nuke and pave if necessary without data loss.

I went to the beta because I had some in-development company code that I needed to exercise with APFS (no problems). I partitioned the fusion drive before going to the beta (and it still has a Sierra startup partition for testing).

I did the APFS testing in a converted partition with two partitions in the new APFS container.

Before HighSierra final, I removed the APFS stuff leaving an HFS+ partition in its place.

High Sierra final fell cleanly onto the machine, which has been running well throughout this adventure.
Doug Lerner  2017-09-26 10:53
This page here - - says APFS works with a regular HDD and will boot from it.

1. Can I use Apple File System with my existing hard disk drive?

Yes. Apple File System is optimized for Flash/SSD storage, but can also be used with traditional hard disk drives (HDD) and external, direct-attached storage.

2. Can I boot macOS High Sierra from an APFS-formatted hard disk?

Yes. macOS High Sierra supports Apple File System for both bootable and data volumes.

Karen Kirtland  2017-09-26 17:39
I am still on Yosemite, and I am very happy there is Tidbits and Joe Kissell to help me decide whether to upgrade. I have no idea what APFS, HFS+, HEVC or any of the other acronyms stand for or what their presence/absence means.

However, I know that when I have to learn them and their meaning, Joe and Tidbits will be there explain the technical language and help me with upgrades, problems, slow downs and whatever other disasters come. Thank you.
B. Jefferson Le Blanc  2017-09-26 19:31
If Apple stays true to form, they will no longer be providing security updates for OS X 10.10 Yosemite. Which means you will stay there at your own risk. For what it's worth, I suggest you upgrade to El Capitan at least in order to remain under Apple's security umbrella. I moved from OS X 10.9 Mavericks to Sierra with few problems—I had already upgraded the utilities I use to Sierra compatible versions.
Eric Stefanski  2017-09-26 21:22
"Apple has now released macOS 10.13 High Sierra via the Mac App Store for all Macs running OS X 10.8 Mountain Lion and later."

This is incorrect. An early 2009 24" iMac, for example, can run ElCapitan, but can't upgrade beyond that; late 2009 iMacs can be upgraded. The early 2009s shipped with Leopard; the late 2009s with Snow Leopard (which may or not be relevant).
B. Jefferson Le Blanc  2017-09-27 07:46
Perhaps it's not so much incorrect as incomplete. The implication I took was that you had to be running Mountain Lion or later to download and install High Sierra. An amplification about the compatible hardware was, perhaps, called for as well since it's clear, from your response, that it's possible to draw the wrong conclusion based on software alone.
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-27 10:34
Yes, that was more of an ellision that might have been ideal. What I was trying to point out is that Apple says that 10.8 is the minimum requirement for upgrading to High Sierra, so if you're running an earlier version, it might not install. Joe thought the minimum was 10.7.5 in the betas; we're not sure what changed.

As far as Mac hardware compatibility goes, it's everything that can run Sierra, and Joe has the full list in "Take Control of Upgrading to High Sierra."
Eric Stefanski  2017-09-27 16:02
No, actually, it was incorrect. "For all Macs running OS X 10.8 Mountain Lion" *is* a hardware statement; it states that "all macs" running 10.8 can upgrade, not that a Mac has to be running at least 10.8. It's not that I drew an implication or came to an incorrect conclusion, but that it is what was written. I knew beforehand what was intended (it's pretty obvious if you know the requirements); but what was written not only missed that but ended up presenting a factual error. Your comment actually led Adam not to recognize the error that exists, instead of correcting it.
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-29 09:45
B. Jefferson Le Blanc  2017-09-27 07:57
Adam, I have a concern about what I've read about how upgrading to High Sierra applies a firmware update to the computer. Does this firmware upgrade impact the viability of downgrading to Sierra or any other version of the Mac OS that may have pertained before the upgrade?

Also, from what I've read, you cannot write to an APSF volume from an HFS+ boot drive, which would mean that one would need to upgrade any utility disk you might use to APSF in order to run a maintenance utility, even Disk Utility. ?
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-27 10:38
My understanding is that no, the firmware update that's necessary for APFS will not affect the Mac's ability to boot from HFS+ in any way. It's merely additive.

And no, I don't think what you're saying is correct about a Mac booted from HFS+ not being able to access an APFS volume. It must be running High Sierra, but HFS+ is not a problem.
James Bailey  2017-09-27 13:46
During the beta, I installed High Sierra on my MacPro (trashcan) via an external SSD. It appeared that the firmware update was installed since the Mac did a reboot in the middle of the install. I had no problem using Sierra as my primary OS until the release of 10.13 (High Sierra).
paulito  2017-09-27 08:37
can anyone pls help me with this tiny problem,i hv an iMac running mountain lion then i upgrade to was hell coz the imac is running very slow,with other several issue.i managed to downgrade back to M.LION ,The ques ,is it ok for me to upgrade to high sierra?i will be grateful if someone can give me some advise
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-27 10:41
If you were able to upgrade to Sierra, you can technically upgrade to High Sierra.

Whether that will address your performance issues, I can't say. It's not uncommon for a Mac to be slow for a while after upgrading as Spotlight rebuilds its databases, but it shouldn't persist for more than a day at most, I wouldn't think.

My approach would be to upgrade to High Sierra, and if there was a performance problem, do a clean install of High Sierra again. Joe's "Take Control of Upgrading to High Sierra" has all the instructions for that (link is above in the article).
B. Jefferson Le Blanc  2017-09-27 10:14
OK, so I've done some reading in Scholle McFarland's Take Control book on High Sierra and it clarified a point for me:

You cannot use APFS on a Fusion Drive (like the one in my iMac) in the release version of High Sierra. Unfortunately, for those brave souls who were testing the beta version, which could use APSF, if they formatted their Fusion Drives to APSF, they will have to back up their files and reformat the drive to HFS+ to use the release version of macOS 10.13. Apple provides a tricky procedure using Terminal to create a High Sierra installer disk from which you can erase the Fusion Drive and then reinstall High Sierra and restore you files using Time Machine, if that was your backup medium.

In any case, the latest iteration of DiskMaker X, version 7 (, is compatible with High Sierra and it's much easier to use than Terminal. I guess I'll have to make another donation to the developer. ;-)

So I won't have to worry about the new file system for awhile. Whew!
Josh Centers  An apple icon for a TidBITS Staffer 2017-09-27 12:06
Yes, correct, though Apple says that APFS is coming to Fusion Drives eventually.
Steve Nicholson  2017-09-27 15:11
Does upgrading to High Sierra mean being stuck with iTunes 12.7? If so, I'm holding off as long as possible. I don't want to lose the ability to use iTunes to manage my iOS apps.
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-27 18:00
No, you can upgrade to High Sierra without updating to iTunes 12.7. I'm not yet sure in what situations iTunes 12.7 is required — 12.6 seems to be able to sync with my iPhone 7 running iOS 11.0.1 fine.
Lindsey Thomas Martin  2017-09-28 13:30
If you are using Adobe's Creative Cloud, do not upgrade to High Sierra. See the article 'Mac Users Should Not Upgrade to High Sierra Yet' at and included links to Adobe forums and announcements.
Adam Engst  An apple icon for a TidBITS Staffer 2017-09-29 09:46
Yeah, it's distressing that Adobe hasn't fixed this already, and that it wasn't reported sooner.
Lindsey Thomas Martin  2017-09-29 19:22
Yes, it is not as if this were an error deep in the plumbing triggered by an obscure corner issue.
I just found out the Final Cut Express is broken under High Sierra, $300 to upgrade to the Pro version! I wish they would provide an upgrade path for a discount!
mikejjj  2017-09-29 08:15
I need to reinstall USB fax modem capabilities after upgrading to High Sierra; I had fax modem capability with Sierra using instructions previously posted here and on GitHub (Reinstall USB Fax Modem Capabilities on macOS Sierra ) However I now get "Hold for Authentication" in the fax window after submitting a job. Any ideas ?
Doug Lerner  2017-10-01 10:05
I upgraded my MBP (late 2013 retina, 512 GB SSD, 16 GB RAM) to High Sierra tonight. It took about an hour from download to upgrade complete.

No problems so far. All my open applications opened up.

The SSD was converted automatically to APFS.

When done my free space went up from 90 GB to 135 GB.