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User profile for user: zttztt
zttztt Author
User level: Level 1
25 points

Can't see time machine backups older than one day

Hi there. I don't know when this started occurring but I am no longer to see Time Machine backups older than one day. This is happening even when hourly backups have been running for several days, i.e. a backup done on Sunday won't appear on Tuesday.


The computer I'm using:

  • iMac M1, 2021
  • Sequoia 15.2
  • Storage: 895.9 GB of 994.66 GB used


The NAS I'm using as a backup drive:

  • Synology DS218
  • OS: DSM 7.2.2-72806 Update 2
  • 4TB x 2 HDD (dual back-up, as I, a layman, understand it)
  • Wireless connection to iMac. WiFi is working fine, with no hiccups.
  • The original Time Machine sparsebundle was created in December 2022.
  • Sparsebundle size of 1.07TB.
  • Volume (shared folder quota) for the Time Machine sparsebundle is set at 3TB.
  • As per Synology instructions, the volume is formatted Btrfs.
  • I have followed the Synology Time Capsule set-up to the letter, no deviation.
  • Hibernation of NAS turned off (I have also been trying to solve for problems of backups failing; that started in Dec 2024 IIRC. So far, turning off hibernation appears to have helped address the backups failing.)
  • The supposedly hourly backup takes over 1.5 hours just to get past the "preparing to back up..." stage.


I have read other old threads in the Support Community that go back several years regarding problems based on an OS they were running way back then. Haven't found anything more recent.


Here is a snippet of the com.apple.TimeMachine.SnapshotHistory.plist file to show how far back it should be going, in case this helps. For brevity, I've not posted the entire file contents.


<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">

<plist version="1.0">

<dict>

<key>Snapshots</key>

<array>

<dict>

<key>com.apple.backupd.SnapshotCompletionDate</key>

<date>2022-12-20T14:01:51Z</date>

<key>com.apple.backupd.SnapshotName</key>

<string>2022-12-20-060151.backup</string>

</dict>

<dict>

<key>com.apple.backupd.SnapshotCompletionDate</key>

<date>2022-12-28T19:32:07Z</date>

<key>com.apple.backupd.SnapshotName</key>

<string>2022-12-28-113207.backup</string>

</dict>

<dict>

<key>com.apple.backupd.SnapshotCompletionDate</key>

<date>2023-01-08T04:10:23Z</date>

<key>com.apple.backupd.SnapshotName</key>

<string>2023-01-07-201023.backup</string>

</dict>


I really don't want to lose the old backups, just in case.


All help greatly appreciated!



iMac 24″, macOS 15.2

Posted on Jan 22, 2025 11:50 AM

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4 replies
User profile for user: Tesserax
Tesserax
User level: Level 10
153,462 points

Jan 22, 2025 12:34 PM in response to zttztt

FWIW. My experience with using a Synology NAS for Time Machine, is basically 180º of that John Galt has experienced. I replaced my aging Apple Time Capsules with a Synology DS916+ back in 2016 and only had one issue with TM since then ... and that issue was resolved by updating DSM on my NAS.


My NAS is currently running DSM 7.1.1-42962 Update 7 ... which is currently the latest (as of 1/22/25) for my NAS model ... which appears to be two years older than your DS218. My NAS is connected to my network by Ethernet, as is the 2023 M2 Pro Mac mini, running macOS Sequoia 15.2, I use for TM.


I used the following Synology KB article to initially setup up the NAS for TM:


I also keep this KB article handy, but never had a need to use it:


To help troubleshoot to the potential cause of why your Mac is experiencing issues with TM backup to your NAS, I suggest an excellent (& free) tool, created by The Eclectic Light Company, called: TimeMachine Mechanic.


It basically parses through your Mac's logs to identify where TM processes may have failed to complete properly, which greatly helps in narrowing down what to do next. In addition, TELC has many in-depth articles on the TM processes that will be worth reading to better acquaint yourself with some of the mystery that goes on in the background.

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User profile for user: John Galt
John Galt
User level: Level 10
148,260 points

Jan 22, 2025 12:09 PM in response to zttztt

Contact Synology: Contact a third-party vendor - Apple Support


Better yet, don't waste your time. They will blame everyone — you, Apple, your network, the phase of the moon – everyone but themselves. That's what I concluded years ago: that their NAS product would never be reliable with Time Machine. After wasting too much of my time they refunded my money.


  • I have followed the Synology Time Capsule set-up to the letter, no deviation.


If there is such a product I'm not familiar with it. I use Apple Time Capsules exclusively. Too bad Apple discontinued them.

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User profile for user: Tesserax
Tesserax
User level: Level 10
153,462 points

Jan 22, 2025 1:10 PM in response to zttztt

You should find the app easy to use, and hopefully, give you some indication where the TM backups are failing.


On a different note, I noticed that you have very little storage space left on your Mac. TM will temporarily use up a significant amount every time it runs by creating those TM snapshots. It's how it works. Normally, those are thinned out over time. However, you may want to revisit how to reduce the amount of storage that you are using on your Mac's drive. This could be a culprit in TM backup issues.


Ref: Free up storage space on your Mac - Apple Support

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Can't see time machine backups older than one day

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