Synchronize. Backup. Bootable Backup.
Whatever your backup or sync scenario, ChronoSync has got you covered!
Back to more tech notes


TNCS-0047 - ChronoSync Bootable Backup on macOS 10.15.5 Catalina

June 3, 2020


The release of macOS 10.15.5 has broken the capability to create new Bootable Backups using ChronoSync v.4.9.9 and earlier. Whether a macOS bug or a feature, ChronoSync 4.9.10 implements a work-around to restore the creation of new Bootable Backups.


The macOS 10.15.x generation has introduced the new APFS Volume Group file system feature. This creates two separate volumes for macOS System Files and user Data Files. These two volumes are linked in the system and Finder to present a seamless single file system to the macOS user.

ChronoSync 4.9.5 added support for APFS Volume Group creation and support for macOS 10.15 Bootable Backup. The Bootable Backup Setup Assistant and Bootable Backup Sync Task were updated to guide the user through the steps to properly create this file system and backup Catalina.

If you have an existing Bootable Backup that was created using macOS 10.15.0 through 10.15.4, you can continue to use this bootable backup destination volume and backup your system. The Bootable Backup continues to work.

If you need to create a new Bootable Backup of macOS 10.15.5, then a new procedure must be performed to accomplish this task.


To create a new Bootable Backup of macOS 10.15.5, you must use the Bootable Backup Setup Assistant. Manual creation of a Bootable Backup Sync Task is not currently supported. After running the Bootable Backup Setup Assistant, you still have the opportunity to customize the Sync Task Document prior to running the backup.

The Bootable Backup Setup Assistant will require the backup destination be erased. Use a volume initialized with the APFS File System and follow the steps in the assistant to prepare the volume for backup.

NOTE: If you have an existing external APFS volume with important data on it, you can always select it as the Destination Target in the Bootable Backup Setup Assistant and choose to create a Sibling Volume. This leaves the original volume intact. This option requires that the device have enough free space to house the original data AND a bootable system.

Upgrading a prior Bootable Backup destination volume (say from Mojave or earlier) is not supported. The backup destination volume must be erased.


Econ Technologies, Inc. continues to monitor macOS Catalina betas and updates for changes to the Bootable Backup process and strives to keep customers' systems and data protected. For any additional questions or problems, open a Support Ticket.


Jun-03-2020 - Created Internally.