Maybe Be Careful with OSX Sierra

No, this isn't some highly integrated scam ad telling you to click because something's wrong with your computer. This is an actual post. (No, TPM really hasn't been hacked.) Even though you don't come to TPM for information about Mac operating systems, I wanted to share this unfortunate experience with the Mac users in our audience.

The short version is there seems to be some fairly major issue with the new Desktop/Document iCloud backup system if you try to use the backup service with more than one Mac (which is to say, more than one desktop computer as opposed to iOS device.)

Here's the longer version.

If you use Macs you may have heard that the new version of OS X has a system that automatically uploads all documents in your Desktop and Documents folders to iCloud. This not only gets you a backup, which is nice. It also allows you to access the files on your desktop from your iPad or iPhone or another desktop if you're not at that computer. That's awesome. I was excited to try it. I have a Mac at work, a Mac at home and then also a Mac Air for when I'm not at either place. I also have an iPad and an iPhone. All good.

So today at work I had Sierra start syncing my work Desktop and Documents folders. Later I checked in iCloud and there it all was. Awesome.

What I didn't see were my Desktop files from my home computer. That was odd because I'd upgraded to Sierra at home the night before. So why hadn't it worked from home?

When I got home I checked to see if I'd enabled this syncing operation on my home machine. I hadn't. So I checked the box to enable it. But when I did it said I had too many files or too many nested folders to use this service. I poked around on Google to find out about this because I hadn't seen any reference to any storage limits. I couldn't find any information about this. So I moved some files off my desktop to see if I could get under whatever this limit I was bumping up against.

After moving a bunch of files, I tried again. Success! It let me do it. Then in a flash all the files on my desktop disappeared and were replaced by the files from my work desktop.


This isn't what was supposed to happen. It was obvious to me that in some way the operating system had decided to sync the iCloud version of my work computer desktop to my home machine - not realizing they were two different computers. Seeing that something very wrong had happened I tried to uncheck the checkbox that started the process. There was a message that told me that it wouldn't erase the documents I'd already synced to iCloud. (Cool, I'd hope you wouldn't do that, Apple.) So I said okay.

When I did that everything disappeared. So all the files on my Desktop were gone. All the files in my Documents folder were gone. I know a decent amount about Macs. I looked in the obvious places. My files weren't anywhere. Like I said, I know enough about computers to know that it's very hard to really erase at least a couple hundred gigabytes of data that fast. It might be erased from the file directory. But the data itself can't be wiped that fast. (Yes, I have back-ups. But still.)

I'll spare you some of the interceding drama. I called AppleCare and explained what happened. It was pretty clear to me at this point that the system hadn't been able to make sense of my syncing desktops from two different computers. Somehow it thought it was the same computer.

So I asked the AppleCare guy: Isn't this what this is for? You're supposed to be able to access your desktop from other devices and computers, right? So why is it getting confused about two desktops? This seems so basic.

At this point I got an awkward and cautious but very transparent and helpful reply that Sierra was a new operating system, they've been getting calls with things like this happening and everybody's still figuring out exactly how Sierra manages this kind of situation works.

Now, let me stop there and say the phone support I got was extremely professional, dedicated ... all the good stuff you can imagine. Believe me, I'd say if it weren't. But it was. (I talked to three different support people total.) But those conversations made it clear to me that this wasn't something I'd misunderstood or a situation where there was some button I needed to push and everything would be fine. This was clearly an emerging issue, one they'd heard about from other users and one they didn't have a clear solution to yet.

This obviously was not what I wanted to hear. The guy on the line explained to me that the system was really more intended for users who had a single desktop and iOS devices rather than trying to use this syncing function on more than one desktop. Now, I'm hardly the only person who has two desktop machines. So it was hard for me to believe this was something that hadn't been thought of. I would have assumed this was just some one in a million issue affecting my setup. But again, the support folks had heard of similar issues. Given that there are tens of millions of people who have Macs and lots of them have more than one desktop computer, this must not happen to everyone who tries this. It must not happen to everyone who tries this. But it wasn't something that happened only to me.

I'll spare you all the other details. But the gist is that based on my own experience and discussing this with multiple Apple Care support folks, OS X Sierra had some major problem with syncing multiple desktops and is liable to think a second computer you try to sync is the same as the first one and try to sync over the second computer. Needless to say, that's not good. To explain everything that happened, what we figured out about where it put the data, etc., would take a post five times longer than this one. Suffice it to say, working with the Apple Care folks, I had to erase the entire computer and begin restoring my data from my Time Machine back up.

In other words, if you've upgraded to Sierra I'd recommend not enabling iCloud back-up of your Desktop and Document folders on more than one Mac.

Let me emphasize again, I got very knowledgable, helpful and professional assistance from Apple Care support with this, in over two hours on the phone. They couldn't have been better. But, still, beware.


Since a number of you have asked, I wanted to assemble the following timeline or order of events, based on what happened and and some subsequent research I've done.

1. I enable Sierra desktop sync on my work computer. It backed up as expected and I was able to access it from my mobile devices.

2. At home latter in the evening I attempted to enable back up on my home computer - a similar vintage iMac as my work computer. I'd estimate they're both between one and two years old.

3. On first attempt, after twirling for a while, OSX said I either had too many files, too many files in a single folder or too many nested files on either my Desktop or Documents folder. I do have a very large number of files on my Desktop - quite possible it's well over a 100 gigs. Maybe substantially more and I do have lots of nested folders. I wasn't aware of any storage limits. And I upped my iCloud subscription to 1T. When that didn't work I removed several very large folders from my desktop to get under whatever limit I was hitting.

4. Finally it allowed me to enable Desktop sync. But as soon as it allowed this my computer flashed and everything that had been on my home desktop disappeared and was replaced by the random mix of files and folders on my work Desktop.

5. Realizing something wrong or unexpected had happened, I then attempted to reverse the process by de-enabling Desktop sync. I got a message asking if I was sure I wanted to do this and that no synced data would be erased from my iCloud account. I clicked okay. When I did this all files disappeared from my Desktop and Documents folder. So blank Desktop except for a hard drive icon.

6. This is the point where a clearer explanation from Apple of how this service works would have been very helpful. The extremely long review of Sierra at Ars Technica explains what happens ...

Enable iCloud Desktop and Documents on a second Mac you’ve upgraded to Sierra, one that already has files in its Desktop and Documents folders, and you will momentarily panic, as all of your existing files are removed and replaced with the “canonical” iCloud versions. But don’t worry; everything that was already on your desktop has been moved to a subfolder in the iCloud Desktop folder named “Desktop – [Name of Mac].” From there, move files around however you want to reconcile the desktops on your Macs.

Needless to say this is a pretty big thing for Apple to spring on anyone without warning or explanation.

7. Despite not knowing this, I was able to find the folder in question. It was clear that this was someway of dealing with two different computer Desktops. Indeed, all my files were now in iCloud. The problem was that I knew there was no way all these files could have been uploaded to iCloud so quickly (we're talking about at least 100 gigs. Probably a lot more.) So these files were clearly still on my computer. But OSX was not allowing them to 'see' them on my Desktop. I was only allowed to view and access them through the iCloud folder because OSX had already assigned them to iCloud even though it had not been able to actually upload them.

8. At this point I was already on with Apple Care Support. The support was very helpful, conscientious and professional. But as I noted above, none of the three support people I spoke to were aware of this being part of how the sync service works. So in addition to not explaining to users how this works, Apple does not appear to have explained this within Apple or at least to people at Apple Care.

9. At this point, in what we might call iCloud limbo I still had access to my files. But there was a big problem. Having to upload such a large number of files, the iCloud sync process had stalled. At one point it said it was trying to upload as much as 700 gigs of data. (Given the size of the hard drive that backs up my home Desktop, I think that number had to be wrong, given the amount space still open on that hard drive, etc. But it was a ton of data. Half that amount is totally plausible.) At this point, OSX would only allow me to "see" or access my data in this pre-uploaded iCloud directory. But the actual upload process that would take it out of this limbo - get it from my computer to the actual Apple Cloud had stalled. The real kicker was that - working with Apple Care support - there was no way to stop the upload process.

10. Despite the fact that the support people I worked with hadn't been briefed on this switcheroo feature, as I said, very good support. Realizing we had a big problem, working with the support guy, we went in and confirmed that I had a viable and recent Time Machine back up. We did - from only an hour or so before I started the process. (I had already turned off all my different back up systems once I realized there was a problem and before I got on the phone with support.) We browsed around to make sure everything was there.

11. Having confirmed a viable back up, we made some other attempts to stop the upload process. When those didn't work we tried to restart the machine - first with a soft and then with a hard restart, eventually fully unplugging the machine. When the machine tried to come back on I got a perpetual black screen with the twirl icon which tried to do something for about 20 seconds, went to black and repeated the process. In other, words the computer was hanging and wouldn't restart. We successfully went into safe mode and tried a few disk repair procedures to resolve the problem. None of them worked.

12. At this point we decided that the situation was far-gone enough that, having confirmed a viable back up, we should wipe the machine and restore from the backup.

So that's the whole story. In retrospect, the initial inability to use the service because I had so many files on my desktop might have been a warning. It's also reasonable to say, did it really make sense to try to back up a couple hundred gigs of data to iCloud? That's a decent point. But, again, Apple is the second largest company in the world: I assumed they'd figured this out. Bad assumption. More to the point, there was never any warning or explanation that I wasn't just syncing or backing up my my data. I was having it removed from my computer entirely. In other words, despite what I assumed, this was not a sync or a backup. I had started a process that was deleting all my data from my primary computer and relocating it to an Apple cloud server. That lack of disclosure or explanation seems quite hard to justify. If it had worked, it wouldn't have been as bad. But having giving no warning or explanation of what it was trying to do, OSX proceeded to botch the process and trigger a cascading series of events that lead to the loss of all my data.


Josh Marshall is editor and publisher of