Time Machine says it couldn't complete back up because disk is nearly full, but it isn't
Time Machine says it cannot complete the backup because the disk is nearly full, but it is not. In fact, the Time Machine tab under System Preferences says "2.68 TB available".
Time Machine was working fine for a couple of years, then suddenly started getting this error. I have not made any major file or fold moves recently.
The external backup drive is 4TB G-DRIVE which has always been used exclusively for Time Machine backups. I noticed from the beginning that this single drive shows as two different mount points. Under "About This Mac / Storage", it shows as:
External 4 TB USB Disk
G-DRIVE mobile USB-C
2.86 TB available of 4TB
G-UTILITIES
4.04 GB available of 4.08 GB
I assumed this was normal but perhaps it is not. If it's not correct, I don't know how to correct it.
G-UTILITIES just contains few instructional documents that came with the drive. They are about 30 MB total in size.
Under "About This Mac / Storage", my hard drive that I back up (Macintosh HD), shows "1.52 TB available of 2.12 TB". That is, it is about 71% full.
What do I need to do get the backups running again?
(I see other related posts on similar issues, but they are not quite the same. Most of them refer to Time Machine becoming confused by large file or folder moves which is not relevant in this case. And none of them address the 2 mount points for the single backup drive.)
Please see 4 screen shots below.
Thanks!
@Jean_JD Okay "diskutil list" output is below followed by Time Machine options:
> diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *121.3 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_APFS Container disk2 121.1 GB disk0s2
/dev/disk1 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *2.0 TB disk1
1: EFI EFI 209.7 MB disk1s1
2: Apple_APFS Container disk2 2.0 TB disk1s2
/dev/disk2 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +2.1 TB disk2
Physical Stores disk0s2, disk1s2
1: APFS Volume Macintosh HD - Data 612.2 GB disk2s1
2: APFS Volume Preboot 418.4 MB disk2s2
3: APFS Volume Recovery 611.0 MB disk2s3
4: APFS Volume VM 3.2 GB disk2s4
5: APFS Volume Macintosh HD 15.1 GB disk2s5
6: APFS Snapshot com.apple.os.update-... 15.1 GB disk2s5s1
/dev/disk3 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *4.0 TB disk3
1: EFI EFI 209.7 MB disk3s1
2: Apple_HFS G-DRIVE mobile USB-C 4.0 TB disk3s2
(free space) 135.2 MB -
3: Microsoft Basic Data G-UTILITIES 4.1 GB disk3s3
/dev/disk4 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *2.0 TB disk4
1: EFI EFI 209.7 MB disk4s1
2: Apple_HFS DR Results 2.0 TB disk4s2
@Ezekiel: The tail of the script output is:
2021-06-04 14:08:30.515135-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Starting automatic backup
2021-06-04 14:08:32.217070-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Mountpoint '/Volumes/G-DRIVE mobile USB-C' is still valid
2021-06-04 14:08:32.220431-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Mountpoint '/Volumes/G-DRIVE mobile USB-C' is still valid
2021-06-04 14:08:33.078935-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Mountpoint '/Volumes/G-DRIVE mobile USB-C' is still valid
2021-06-04 14:08:33.079077-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Backing up to G-DRIVE mobile USB-C (/dev/disk3s2,6): /Volumes/G-DRIVE mobile USB-C
2021-06-04 14:08:33.783037-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:Inheritance] Found matching machine store '/Volumes/G-DRIVE mobile USB-C/Backups.backupdb/K’s iMac' for computer named 'K’s iMac', no machine store inheritance needed
2021-06-04 14:10:38.181495-0600 localhost backupd-helper[288]: (TimeMachine) [com.apple.TimeMachine:PowerManagement] TMPowerState: 2
2021-06-04 14:10:38.182106-0600 localhost backupd-helper[288]: (TimeMachine) [com.apple.TimeMachine:General] Not starting scheduled Time Machine backup: Backup already running
2021-06-04 14:12:19.376008-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Mountpoint '/Volumes/G-DRIVE mobile USB-C' is still valid
2021-06-04 14:12:21.408816-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:LocalThinning] Starting age based thinning of Time Machine local snapshots on disk '/System/Volumes/Data'
2021-06-04 14:12:21.408831-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:LocalThinning] Starting age based thinning of Time Machine local snapshots on disk '/System/Volumes/Update/mnt1'
2021-06-04 14:12:21.409116-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Failed to wait for snapshot deletion to complete on disk '/System/Volumes/Update/mnt1', error: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"
2021-06-04 14:12:21.409354-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:LocalThinning] Skipping age based thinning of Time Machine reference snapshot 'com.apple.TimeMachine.2021-05-26-120858.local' on disk '/System/Volumes/Data'
2021-06-04 14:12:22.250927-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Failed to create APFS snapshot with name 'com.apple.TimeMachine.2021-06-04-141222.local' on volume '/System/Volumes/Data', error: Error Domain=NSPOSIXErrorDomain Code=28 "No space left on device" UserInfo={NSFilePath=/System/Volumes/Data, NSLocalizedDescription=/System/Volumes/Data: No space left on device (error 28)}
2021-06-04 14:12:22.251048-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Failed to create local snapshots
2021-06-04 14:12:22.252183-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Failed to create or mount stable snapshot.
2021-06-04 14:12:23.859850-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Mountpoint '/Volumes/G-DRIVE mobile USB-C' is still valid
2021-06-04 14:12:23.860031-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Mountpoint '/System/Volumes/Data' is still valid
2021-06-04 14:12:24.069831-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:General] Backup failed (50: BACKUP_FAILED_NO_SPACE_FOR_LOCAL_SNAPSHOT)
2021-06-04 14:15:07.075137-0600 localhost backupd-helper[288]: (TimeMachine) [com.apple.TimeMachine:PowerManagement] Thermal pressure level 0 -> 1
2021-06-04 14:15:07.078713-0600 localhost backupd[289]: (TimeMachine) [com.apple.TimeMachine:PowerManagement] Thermal pressure level 0 -> 1
Filtering the log data using "subsystem CONTAINS "com.apple.TimeMachine""
Solution 1:
So I'm by no means an expert on Time Machine internals, but it's important to read error messages carefully and pay attention to grammar. (Apple, as opposed to Microsoft, is usually fairly careful to phrase their error messages precisely.) The error does not complain about the backup disk being full, but rather, about the disk to be backed up, i.e., Macintosh HD - Data being full. Looking at the log messages you posted shows why that is a problem: Apparently, TM tries to make a local snapshot first (presumably so that it can then make the backup without caring about changes to the live FS while backing up), but runs out of space while doing that: /System/Volumes/Data: No space left on device (error 28), Failed to create local snapshots, and Backup failed (50: BACKUP_FAILED_NO_SPACE_FOR_LOCAL_SNAPSHOT).
That's why it also tells you that you need to delete some files on this disk.
You can check with tmutil whether maybe you have a lot of existing local snapshots that you could thin out to make space, try tmutil listlocalsnapshots / and see if that lists previous snapshots or not. If it doesn't, I guess you'll really need to delete some stuff first (or at least move it elsewhere).
Hope this helps!