iCloud sync preventing Time Machine backup, but Optimize Storage is Off

One day ago, I upgraded to Sequoia (from Ventura). Prior to the upgrade, Time Machine was working just fine. Now, Time Machine will not backup because iCloud is perpetually in sync mode. But it is not syncing because the amount of storage used (195 Mb) hasn't changed and because Optimize Mac Storage was OFF before the upgrade and it's still OFF.


How do I get out of this mess?


Thank you.

Mac mini, macOS 15.5

Posted on Jul 23, 2025 09:38 AM

Reply
14 replies

Jul 23, 2025 10:28 AM in response to Howard Fried

It's good that Optimize is turned off, because Time Machine can't back up files that aren't there. My Time Machine is doing fine with iCloud Drive and iCloud Photos.


How is the storage on our Mac and at your iCloud--how much free space do you have? I'm not sure the "amount of storage" updates often enough for that to be a useful measure when things are changing. You need to have plenty of room, more than 10% free, in both places for this to run smoothly. iCloud should have little filing circles as it uploads-- what do you see with those? The meaning of the iCloud icons is near the bottom in this:

Understanding iCloud Drive - Apple Community


You can try turning iCloud syncing on and off to see if that jogs the system. Keep in mind that syncing is slow when the Mac is being used-- it's best to leave it on overnight.


Let us know what happens…

Jul 23, 2025 11:12 AM in response to Richard.Taylor

Thank you for the reply. I don't use iCloud and I never intentionally synced anything. There is one other device on our network, an iPad, but, as I say, I never set up syncing to it.


How do I turn iCloud syncing on and off as you suggest? Optimize is OFF. Desktop & Documents folder is OFF. But now I see a box titled "iCloud Drive," at bottom of which it says "Sync this Mac" and it is ON. Is that what I turn off (if yes, how did it get turned on)?


Only 5% of the original free iCloud storage space is used. That number has not changed, which is why I concluded that syncing was not occurring. I don't know what those files are and, consequently, I don't care about them.


Thanks for any feedback.

Jul 23, 2025 12:31 PM in response to Howard Fried

I had misunderstood you. I thought that "perpetually in sync mode" meant synchronizing with iCloud, but you didn't intend for that to be happening.


iCloud Drive is a folder on your Mac that is copied to the iCloud Drive folder at iCloud.com, and then it's copied to the iCloud Drive folder on other devices, like maybe your iPad, that also have iCloud Drive turned on. The whole purpose of iCloud is to synchronize files and pictures among several devices. Your Desktop and Documents folders can be kept inside the iCloud folder so those would be synchronized, as well. If you don't want the syncing to happen, just turn all the iCloud things off.


Optimize Storage automatically swaps files in and out from iCloud so you don't use so much space on your internal drive. I don't use Optimize on my Mac, because I want the stuff to be there to get backed up, but I do use Optimize on my phone since it has way less space.


As with the threat of AI, when you see it taking over, just switch if off!


Jul 29, 2025 08:30 AM in response to Howard Fried

I'm having a different but related problem - maybe you can help. Twice now I've suddenly seen an iCloud error message that says: "If you continue items will be removed from the Desktop and the Documents folder on this Mac and will remain available in iCloud Drive." Then I have an option to Cancel or Turn Off. (Note: I changed nothing in my iCloud settings before this showed up.)


Both times this happened while Time Machine was backing up but the second time my screen went gray and my whole computer froze until I ran Disk Utility from Recovery Mode. It found a whole long string of errors with Time Machine in the code and seemed to fix them. But I'm afraid it will happen again and would like to avoid that.


I have now gone into System Settings and turned off Optimize Storage, but I want my Desktop/Documents in iCloud, on Time Machine and on my hard drive.


What to do? And if I get that message again, should I select Cancel or Turn Off? Do I need to reinstall Sequoia? Get a new Time Machine disk?


Thanks for any help!

Jul 29, 2025 09:26 AM in response to Jazzo49

Hello Jazzo,


I'm afraid I won't be much help, but here is the conclusion to my story.


Optimize was OFF and Desktop & Documents folder was OFF. Inexplicably, iCloud Drive was ON. I don't recall turning it on. Thus, iCloud was trying to sync (Time Machine reported "Time Machine cannot back up because some iCloud Drive files have not finished syncing."). But there was nothing to sync to. We have only one other device on our network, and I am 100% certain I never set it up to sync.


So, with much trepidation, I switched OFF iCloud Drive and received this message: "If you turn off iCloud Drive, all documents stored in iCloud will be removed from this Mac. Options Remove from Mac, Keep a Copy, Cancel." I selected Keep a Copy, even though I didn't have any (visible) files on iCloud Drive.


Then, another message: "iCloud needs to finish updating before being turned off. Your documents will be copied to a folder named iCloud Drive (Archive) in your Home folder on this Mac. Options Cancel, Stop Updating and Turn Off." I chose the later option, iCloud stopped trying to sync, and Time Machine was able finally to back up.


Regarding your issue, which seems quite different, please note that I'm not a specialist, and you should first contact Apple Support.


From the error messages I got trying to sort things out, it seems that Apple has provided ways so that one doesn't lose everything when making changes to iCloud. Because there were TM errors, perhaps you should turn it off for a while, and let iCloud smooth things out. If there are important files currently not in Desktop and Documents, you might move (copy) them there so they will be backed up in the absence of TM. Have you run Disk Utility on the TM drive? You might try a third party app like Drive DX to check overall drive health.


Best of luck.

Jul 29, 2025 09:28 AM in response to Jazzo49

Jazzo49 wrote: …I have now gone into System Settings and turned off Optimize Storage, but I want my Desktop/Documents in iCloud, on Time Machine and on my hard drive.

What to do? And if I get that message again, should I select Cancel or Turn Off? Do I need to reinstall Sequoia? Get a new Time Machine disk?

You sent your message to Howard Fried, but I'm guessing you meant it for me?


The big disadvantage to "Optimize Storage" is that you can't back up files that aren't there. This applies to both iCloud Drive and iCloud Photos, as it says in the earlier link, Understanding iCloud Drive - Apple Community So I don't use Optimize with my Mac for this reason. I do have files in iCloud Drive that I have removed from my Mac (mostly to see what happens,) and I haven't had problems with Time Machine.


The message you received is prompted when you try to switch off iCloud storage. Your Mac would be left with aliases referring to the actual files at iCloud.com that it could no longer access. So turning off iCloud leaves the files at iCloud.com, but it erases the reference stubs on the Mac.


Just because you've turned off Optimize doesn't mean that all your files have been downloaded from iCloud. Some files may not be returned to the Mac until they are requested. You can look at the iCloud icons (as shown in that link) to see the status of your iCloud Drive files, and you can download the ones that haven't arrived, yet.

Jul 29, 2025 09:37 AM in response to Richard.Taylor

Thank you, both! Yes Richard, I did mean to reply to you. You say the message was prompted when I tried to switch off iCloud storage - but that's the thing, I didn't try to do that. I didn't change or do anything, this just started happening. But the first time it happened, I think I did click turn off, because I didn't like the idea of it continuing and erasing files from my Mac.


The idea of it erasing the reference stubs on my Mac is scary to me. I don't actually use iCloud actively - I had a computer crash before this and pulled Documents/Desktop into iCloud out of fear LOL. I basically live on my Mac.


What do you recommend if I get that message again?



Jul 29, 2025 12:32 PM in response to Richard.Taylor

Ugh - now I'm getting an error message saying "Your system has run out of application memory" when I only have four things open - Outlook, Chrome, Word and Messages. I usually have even more than that open and it's fine. This happened yesterday too. Should I try reinstalling Sequoia? I"m not sure what's going on, but my computer is suddenly becoming problematic.

Jul 29, 2025 01:46 PM in response to Richard.Taylor

Okay, so this link was super helpful, thank you. The key piece of it for me is that iCloud is for syncing not backup. I don't really need to sync documents with my phone or laptop (which has very little space on the hard drive). I guess what confuses me is that I think of Dropbox as being for both syncing AND backup, but I guess they're not really the same?


Anyway, I'm thinking I might stop using iCloud for Desktop and Docs. Thanks for your help again!

Jul 29, 2025 02:15 PM in response to Jazzo49

Syncing is for sharing, so you can work from different devices. Backup is in case you accidentally erase your entire Doctoral thesis and you have to spend another three years taking data. Syncing would immediately erase the thesis everywhere.. But backup doesn't let you access your most current version on another computer.


iCloud provides a limited backup, like if your phone gets run over by a truck, then you can access your stuff from a computer. But if you make a mistake in your work, that mistake is propagated instantly to all of your devices.


Syncing is a luxury. Backup is essential.

iCloud sync preventing Time Machine backup, but Optimize Storage is Off

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