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Time Machine won't go back in time

I can enter Time Machine and navigate but cannot go further back in time. The time hashmarks on the right turn red when I hover the cursor. I have run First Aid from Disk Utilities and the disk checks out healthy. Does this situation indicate that the data is corrupt? If so, what's the process for correcting it?


I'm using a 1-TB USB external powered hard drive for T.M., backing up a late-2015 iMac running OS 10.13.6, High Sierra.

iMac Line (2012 and Later)

Posted on Jul 31, 2019 3:54 AM

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Question marked as Top-ranking reply

Posted on Aug 6, 2019 12:25 PM

For fundamental troubleshooting references please read If you can't back up or restore your Mac using Time Machine - Apple Support and Time Machine troubleshooting - Apple Support.


I have run First Aid from Disk Utilities and the disk checks out healthy.


Repeat that exercise with the source volume. You have to boot macOS Recovery first and select Disk Utility from the macOS Utilites menu, since DFA cannot "repair" the volume on which it's running.


Does this situation indicate that the data is corrupt?


Not necessarily since TM's file storage events database is maintained on the source. That's the reason for running DFA on it. The backup disk might have suffered corruption regardless of what DFA concluded, which is the reason at least one additional, redundant Time Machine backup drive is advisable. Any backup is better than none, but one and only one backup device does not comprise a robust backup strategy. For that reason I suggest getting another one at your earliest convenience.


Then consider the following:


---


The following technique can be used to "reconnect" to the backup disk, which will force a traversal of the backup hierarchy. It will not affect TM's existing backup history in any way.


Open Time Machine's Preferences and de-select the Back Up Automatically checkbox. Make sure no backups are in progress, otherwise you should wait for it to finish or terminate.


  • If the backup disk is directly connected to the Mac, disconnect it: drag its icon to the Trash, wait for it to disappear from the Desktop, and then physically disconnect it from the Mac.
  • If its icon does not appear on the Desktop, select External Disks in the Finder menu > Preferences... > General. You can de-select it later.


Then, click the "Select Disk..." button, select the backup disk, then Remove Disk, then Stop Using This Disk.


  • If you designated more than one backup destination, the "Select Disk..." button is replaced by an "Add or Remove Backup Disk..." option. You have to scroll through the list of backup disks for that option to become visible.


This will not affect any existing backups.


Reconnect the backup disk to the Mac, power it on if required, and wait for its icon to appear on the Desktop.


Then, Select Disk... again in Time Machine's Preferences. Re-select the same one under Available Disks, then Use Disk. If the backup is on a network (TC or AEBS), you will be prompted for the password you provided for that disk in AirPort Utility.


"Waiting to complete first backup" will appear, which means it won't do anything until the next scheduled backup. Despite the implication of that message, it does not mean it needs to create a completely new backup, as if it's creating a brand new one. Your existing backups will still be available.


If you don't want to wait that long, select Back Up Now.


A Notification may appear if your source volume is encrypted and the backup volume is not. That's normal.


Re-select Back Up Automatically. The "Preparing Backup..." status message will remain for a long time. Eventually, "Backing up xxx of yyy" will appear, but those values will not be accurate, nor will the "Estimated time remaining" in Time Machine's Preferences. Just ignore it. It may take a few hours even if your Mac is not allowed to sleep. Time Machine will also pause or become slow if you use your Mac for tasks it considers a higher priority.

15 replies
Question marked as Top-ranking reply

Aug 6, 2019 12:25 PM in response to bookmanjb

For fundamental troubleshooting references please read If you can't back up or restore your Mac using Time Machine - Apple Support and Time Machine troubleshooting - Apple Support.


I have run First Aid from Disk Utilities and the disk checks out healthy.


Repeat that exercise with the source volume. You have to boot macOS Recovery first and select Disk Utility from the macOS Utilites menu, since DFA cannot "repair" the volume on which it's running.


Does this situation indicate that the data is corrupt?


Not necessarily since TM's file storage events database is maintained on the source. That's the reason for running DFA on it. The backup disk might have suffered corruption regardless of what DFA concluded, which is the reason at least one additional, redundant Time Machine backup drive is advisable. Any backup is better than none, but one and only one backup device does not comprise a robust backup strategy. For that reason I suggest getting another one at your earliest convenience.


Then consider the following:


---


The following technique can be used to "reconnect" to the backup disk, which will force a traversal of the backup hierarchy. It will not affect TM's existing backup history in any way.


Open Time Machine's Preferences and de-select the Back Up Automatically checkbox. Make sure no backups are in progress, otherwise you should wait for it to finish or terminate.


  • If the backup disk is directly connected to the Mac, disconnect it: drag its icon to the Trash, wait for it to disappear from the Desktop, and then physically disconnect it from the Mac.
  • If its icon does not appear on the Desktop, select External Disks in the Finder menu > Preferences... > General. You can de-select it later.


Then, click the "Select Disk..." button, select the backup disk, then Remove Disk, then Stop Using This Disk.


  • If you designated more than one backup destination, the "Select Disk..." button is replaced by an "Add or Remove Backup Disk..." option. You have to scroll through the list of backup disks for that option to become visible.


This will not affect any existing backups.


Reconnect the backup disk to the Mac, power it on if required, and wait for its icon to appear on the Desktop.


Then, Select Disk... again in Time Machine's Preferences. Re-select the same one under Available Disks, then Use Disk. If the backup is on a network (TC or AEBS), you will be prompted for the password you provided for that disk in AirPort Utility.


"Waiting to complete first backup" will appear, which means it won't do anything until the next scheduled backup. Despite the implication of that message, it does not mean it needs to create a completely new backup, as if it's creating a brand new one. Your existing backups will still be available.


If you don't want to wait that long, select Back Up Now.


A Notification may appear if your source volume is encrypted and the backup volume is not. That's normal.


Re-select Back Up Automatically. The "Preparing Backup..." status message will remain for a long time. Eventually, "Backing up xxx of yyy" will appear, but those values will not be accurate, nor will the "Estimated time remaining" in Time Machine's Preferences. Just ignore it. It may take a few hours even if your Mac is not allowed to sleep. Time Machine will also pause or become slow if you use your Mac for tasks it considers a higher priority.

Time Machine won't go back in time

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