User level: Level 2 (388 points)Unable to mount APFS containers on partitioned external drive
I have a 5GB drive with two partitions. One is used for Time Machine, and the other is for general storage. I have tried using Disk Utility but no joy. The Time Machine partition has a password, which I have used, but I get a message saying there is an error which prevents unlocking the drive. Any suggestions?
Posted on Oct 8, 2026 3:29 PM
User level: Level 9 (74,110 points)Oct 14, 2026 10:35 AM in response to Lee Rodgers
When an encrypted APFS Time Machine partition refuses to unlock and other partitions fail to mount, the underlying APFS container or file system catalog is usually damaged or failing to decrypt properly through Disk Utility's graphical interface.
User level: Level 7 (26,777 points)Oct 15, 2026 5:33 PM in response to Lee Rodgers
Hi Lee,
May I suggest using a separate external drive for your general data? External drives can be backed up along your Mac data with Time Machine. (You just have to remove them from the Time Machine exclusion list for them to be backed up.) You would get some peace of mind knowing that your general data could be restored.
User level: Level 2 (388 points)Oct 15, 2026 2:01 PM in response to WheelieNick
I tried to fix this anyway I could, even using the terminal. But...no joy. I ended up erasing the disk and starting over. Sigh. Thanks for the comments.
Originally posted at discussions.apple.com/thread/256372786