TimeMachine and Big Sur

Big Sur changes the TimeMachine required format to APFS. This effectively makes the MyCloud EX series incompatible with TimeMachine.

Does anyone have advice on changing the format of My Cloud partitions?

Thank you.

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Update - WD is reviewing this case.

Hi, I’m having similar issues. Upgraded to Big Sur and then my Time Machine backups immediately stopped working. I have an older 2Tb MyCloud device (about 3 years old).

It’s really disappointing. I’ve a new MacBook coming soon, so am now faced with needing to buy new hardware to backup and transfer my data.

It would be good if WD could provide some guidance on if this issue will be fixed and when.


I also spoke with Apple about this, there response was not much better. Since exiting the router/storage business (ie. Time Capsule). Apples near term answer is dedicated attached USB drives. There’s a rumor of an iCloud solution on the horizon, but that a long way away.

The current answer is to transfer the file to a APFS disk, which means either a dedicated on-site drive.

I’ve not identified a NAS which will support APFS so even if WD attempts to pursue this path it may take some time.

Any recommendations for a NAS that supports APFS will be appreciated.

Thanks kworden, sounds like a USB drive (in the short term) is the way to go. My router allows an external USB to be attached for storage, I may be able to add one on there (formatted) correctly. If not it looks like it’s back to the old fashioned cable method (circa 2000).

Update - No Progress
Aaron S: So as i referred to your previous case history and if you are not able to configure as guest as well as registered user
KWORDEN: correct
Aaron S: Let me escalate the case to concerned department to check the issue and you will be updated via email
KWORDEN: Ok … what I’d like to know is if WD is working on a solution. I’m aware that this may take some time, but I’d like to know one way or the other. If WD is not addressing the issue, I’ll need to look for another solution.
Aaron S: As the My cloud logs are also reviewed it may take time as soon as we get an update we will surely update you

APFS is needed for Direct Attached Storage (DAS) devices and not Network Attached Storage (NAS) devices. My Cloud OS3 and My Cloud OS 5 both support the TimeMachine backup of macOS 11 BigSur by configuring the mac to use the TImeMachineBackup share on the My Cloud.

Super, please provide instructions for how to make that work.
Specifically, Mac OS 11 TimeMachine requires a APFS formatted target. I’m excited that you’ve figured out how to make the NAS work on a non-formatted target, looking forward to your comprehensive response.

@kworden APFS is not required for TimeMachine Backups over the network to a NAS device.

Starting macOS Time Machine Backups to My Cloud and Network Attached Storage

Answer ID 2374

@SBrown Thanks. However, that article doesn’t address MacOS 11 or TimeMachine requirements under OS 11.

As detailed in case [201115-000130] the current methods for enabling Time Machine on a NAS are not effective. The community is waiting for WD to:

  1. acknowledge or decline support for TimeMachine running on MACOS 11 on a NAS.
  2. provide a timeline for implementation if WD will support it.

Update - WD spent about an hour in a remote session verifying that timemachine under MACOS 11 does not work with MY Cloud OS5. I’m not sure if that’s progress or not. We’re basically back to the original problem statement, but it’s been confirmed by WD Staff.

However, it does suggest that very little if any testing was done between the My Cloud product series and the Mac OS prior to its release.

It’s not a matter or APFS, it should be a matter of TimeMachine over SMB support, which was pointed out in the release notes.

Have you been able to start a backup with the SMB protocol? I guess it should be transparent if correctly implemented. However there is a command line to do so.

I’ve not been able to start a backup with SMB and Mac OS 11.

Could you show screenshots of the TM preference panel?

The terminal line goes like this:

sudo tmutil setdestination smb://guest:guest@NAS_IPADDRESS/TimeMachineBackup

As explained here: https://support-en.wd.com/app/answers/detail/a_id/21360


I did attempt to use that command. it had the same results as using timemachine preference to select the disk. “The back up disk image could not be created” see attached.

When you overlap the destination disk in the TM preference panel, does it show a smb:// address or a afp://?

What SMB version is set on the My Cloud? Is AFP still on?

Trying blindlessly here.

TimeMachine preference panel shows smb:// address
SMB is set to V3
AFP is on … note that if you turn it off, MAC backups is also turned off and the share is not visible to TimeMachine.

Thanks for sharing!
Did the terminal command end with an error? What number?
You are indeed logging in as a guest?

The terminal command did error, I don’t remember the number but the text was the same as the TimeMachine panel. I’ll run it again after my current backup finishes (on a USB drive).

Yes double checked to ensure that I logged in as a Guest.

@AustinForest, set the backup destination using
sudo tmutil setdestination smb://guest:guest@NAS_IPADDRESS/TimeMachineBackup

No error … when timemachine was run received the same error “the backup disk image could not be created.”