2019 iMac running Sequoia 15.7.8. Replaced a full 4TB back up drive with new 5TB. The initial backup failed to complete even after moving 100% to the drive and finishing clean up. Now get error "Backup not completed TM couldn't back up to new drive"
iMac 27″, macOS 15.7
Since the backup reached 100% and then failed during the cleanup/finalization phase, the issue is usually not the copying itself.
It is more commonly caused by one of these:
Here's the order I'd troubleshoot it.
Check the drive format
Run First Aid
Erase and start fresh
Avoid hubs or adapters
If the drive is connected through a USB hub or dock, connect it directly to the iMac. A brief disconnect during the final verification can cause exactly the error you're seeing.
Since the backup reached 100% and then failed during the cleanup/finalization phase, the issue is usually not the copying itself.
It is more commonly caused by one of these:
Here's the order I'd troubleshoot it.
Check the drive format
Run First Aid
Erase and start fresh
Avoid hubs or adapters
If the drive is connected through a USB hub or dock, connect it directly to the iMac. A brief disconnect during the final verification can cause exactly the error you're seeing.
Finally worked!!!
After erasing the hard drive and starting over I chose unencrypted option, keeping APFS formatting.
Not sure but I think my initial choice of encrypted made a separate volume and had to be erased.
Again thanks to all who responded!!
How is the new drive formatted? APFS or FAT? Or macOS Journaled? My backup drive is formatted as macOS journaled, you might want to try that
What make, model and brand is this 5 TB drive ?
It is USB Powered of Self Powered ?
You mentioned checking for some Security Software
To avoid a game of 20 questions
Download the Application Etrecheck ( External Link ) directly from the Developer.
This is a Diagnostic Tool that makes no changes to the computer.
It makes a coherent and readable inventory of both the Hardware and Software used on the computer
The application is free or paid for added features.
The Report will Not Reveal Any Personal Information.
Post back the Full Report - Share Report >> Copy , then paste >>>> using the Additional Text Icon <<<<
Is the replacement drive a HDD or an SSD? If a HDD, it should be formatted as HFS+; for SSDs, it should be formatted as APFS.
Thanks for everyone’s suggestions. I started by connecting the new external hard drive directly to my iMac using the USB- C cord it came with. I then reformatted the external hdd to APFS as initially instructed and selected it encrypted back up. After it failed during clean up, I ran disk utility on the Time Machine (APFC, guid partition map) container, volume and disk. They all checked out “OK.” I then searched for any anti virus software that could be interrupting the clean up. Found none so I paused Backblaze just in case. ( during that search, I went down a rabbit hole trying to figure out why I had a credence cryptic asset disk attached via dmg. Found it’s apparently related to sequoia updates but unrelated to Time Machine.) I finally erased the new external HDD and started over without encryption. If this fails too I will try reformatting the disk to Mac OS journaled and if that fails as well I supposed I could try HFS+ but I don’t understand why that would work. Please explain.
charyizquiedo wrote:
Finally worked!!!
After erasing the hard drive and starting over I chose unencrypted option, keeping APFS formatting.
Not sure but I think my initial choice of encrypted made a separate volume and had to be erased.
Again thanks to all who responded!!
Thank you for the followup
Hearing that the issue was resolved is always good news đź‘Ť
🦉-53
FYI ... HFS+ = Mac OS Extended (Journaled) ... so there is no need to format for each type, as they are the same.
I've actually used etrecheck before. Didn't occur to me to try it for this. My 73 year old brain isn't retaining as much as it used to. Wetdrive maybe faulty :-)
From one 73 year old, to another of similar age as you
All my internal RAM is getting too full with other more impotent matter, lol
Time Machine backup fails to new 5TB drive on 2019 iMac
