Is it possible make time machine backups to an disk plugged into an Airport Extreme base station when the disk is formatted as Mac OS Extended Journaled?

I've tried formatting the disk in this way, but whenever I connect it to the base station Airport Utility gives me the "disk needs to be repaired" error message (with no instructions on how to repair it). Tried using the repair tool in Disk Utility, but that had no effect.

Connecting the disk to the drive formatted as Mac OS Extended (with no journalling) seems to work, but I'd rather have journalling turned on for the extra stability that it offers.


No, the AirPort Extreme Base Station does not support journaling. It only supports regular HFS+.


To expand on Spiff's answer, Apple has a support document that mentions this towards the end of document.

Time Machine support for USB disks

OS X Time Machine supports compatible unencrypted USB disks connected to AirPort Time Capsule (802.11n and 802.11ac), and AirPort Extreme (802.11ac)."

So, it appears you have an AirPort Extreme 802.11n (not supported), and not an 802.11ac (which would be supported). (I would recommend updating the question to specify which model you have, for added clarity.)

When reading the support document don't be confused by the quote below that is towards the top of the document (it tripped me up at first). It mentions journaling support, but is only in reference to attaching USB devices in general, and does not include TimeMachine support:

Supported formats

Mac OS Extended (HFS-plus) - Formatting a storage device as Mac OS Extended with journaling is recommended, because it may provide additional resilience if the device is removed or powered down while in use.

So we can see according to these two quotes that you can use the drive as a normal network attached drive with the base station that you have with journaling enabled, as long as you don't use TimeMachine, which is consistent with your experience. But For TimeMachine to work with journaling you'd need a Time Capsule or AirPort Extreme 802.11ac.

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