Time Machine not backing up automatically

FWIW. I have a 2023 M2 Pro Mac mini and one of my Time Machine back up destinations is a Synology 916+ NAS. My Mac is also running macOS Sonoma 14.2.

Time Machine with this NAS has been flawless since macOS High Sierra (with a different Mac mini at that time), with one hiccup when I upgraded to macOS Monterey. After doing so, I started having similar issues with TM as you are experiencing. The solution was to upgrade the NAS operating system. Once done, the issue has disappeared and remains so with my M2 mini.

There are a number of potential troubleshooting steps you can take to try to determine what the issue may be that is preventing your Mac from successfully using TM with your NAS. I would first check to see if you are running the latest version of Synology's DSM.

If you are, then I suggest that you try Mints from The Eclectic Light Company. It's free and you can learn a bit more about it with this link:

• https://eclecticlight.co/2020/07/17/time-machine-16-reading-a-normal-backup-in-catalina-using-mints/ << Although this was written around macOS Catalina, it still is applicable with Sonoma.

You may also find the following articles helpful:

• Time Machine troubleshooting on Mac - Apple Support
• Verify your backup disk on Mac - Apple Support

After a few days, I think I have discovered the workaround. At least so far, it is working for me. The problem seems to be that Time Machine cannot create the first backup sparsebundle. I back up to three different media. My Mybook NAS, a Time capsule that I upscaled to 4TB, and a 2TB external (USB) portable. So here is the workaround:

1. Create a backup sparsebundle on an attached drive or a hi-cap Thumb Dive
2. Copy the new sparsebundle to the NAS Time Machine folder
3. Go back to the Mac after the copy of the sparsebundle has loaded into the NAS
4. Point the time machine at the new NAS sparsebundle and tell it to backup.

Mine has been working like a champ ever since.

I've been looking for a solution to Sonoma and time machine back up for a while. I migrated from a 2017 MB to a 2023 MBAir with Sonoma. I realized after reading through the various posts about this issue that it is not one issue. Very disappointed in Apple's efforts toward a solution on this. For me it was some authentication issue with the shared network drive. I tried various log in items, background items, terminal commands etc. all yielded no resolution. I hope this helps someone.

My solution that worked:

Turn off icloud drive > Restart > remove time machine drive from system pref> restart> disconnect from Mac mini> reconnect to mac mini using Admin account > restart> mount share drive from mac mini on drive '23MB> go to time machine setting and add mounted shared drive> verify previous backup> restart> back up now option from time machine tool bar menu.

**eureka** it started backing up. It was not a new backup as there was only 4GB of data that was copied. My drive is at 130GB used up so I knew it was adding to the existing back up since its been about a month since I could not update the time machine back up.

I'm so disappointed in Apple's response to this issue as my backup system has files that go back to my 2003 PowerBook. All of a sudden have to trouble shoot this for a brand new device on a back up system thats been working for so long. Since 2014, I have been using a 8TB OWC rack mount raid drive attached to a Mac-mini(2013). Additionally my partner's 2018 MB also backs up to this drive since 2020 as well. This has been used flawlessly for three devices including the mini backing up to its own image on the raid drive. I even restored a machine after soda spill/device replacement under applecare and was very glad to have this system in place.

Thanks for providing your solution. Curious, you mention that you have a "My Mybook NAS." WD make a number of these devices, which exact model do you have?

For example, I have a WD My Book Pro. It's basically a self-contained file server that connects directly to my Mac by Thunderbolt. As such it is NOT a NAS. Just want to make sure what you have, as I also have a dedicated Synology NAS that is connected to my local network by Ethernet.

WD MyCloud EX4100 (RAID) 4 x 4TB configured in RAID 10 — It's definitely a NAS. It is connected by EtherNet to my 16-Port switch. I have part of it assigned as a Time Machine Backup. It was flawless until Sonoma. I worked for four days to get this figured out, blaming the cabling, the switch, the ethernet port on the Mini, and on and on. I formatted and re-built the Mac mini, and reformatted the NAS twice before finding this solution.

Thanks! FWIW, I didn't come across this issue with my Synology NAS. It's the same one I have had for a few years with Mac running everything from macOS High Sierra to now, Sonoma. The only "bump in the road" where TM was not able to perform a backup, was when I upgraded to macOS Catalina. For me, the "fix" was to update the Synology OS. There way no need for me to start a fresh backup. Not sure if that would work for your WD.

Regardless, I'm glad you found a solution for your NAS. I'm sure it will help others who also have this WD NAS.

The WD NAS is at the latest firmware update. I'm sure this is one of those problems that will have WD blaming Apple and vice versa. I was converted to the MAC when we were running OS 6 and an Appletalk Network on a twisted pair of telephone cables. We didn't even have colour back then. I was the net admin for the first functioning network on the RCAF base I was posted to. We have come a long way since. 😁

We have indeed! My first Mac was an Apple IIc and wrote my thesis on a Commodore 64. Ah the good ole days.

Happy New Year!