Time Machine Backup Disk Not Found - MacBook via Google WiFi to NAS

Thank you for your suggestion!

As you pointed out, the problem indeed stemmed from the fact that not all devices were on the same subnet. Bonjour protocol, which Time Machine relies on to detect the NAS, cannot discover devices across different subnets.

In my home setup, Google WiFi creates a separate subnet from the main router (which also serves as the ONU), meaning that when the NAS was connected to the main router, Time Machine couldn't detect it. Since I wanted to use Google WiFi’s DHCP for my devices, I needed to place the NAS on the same subnet as the devices connected to Google WiFi.

Therefore, I ended up connecting the NAS directly to Google WiFi via Ethernet. Wireless was not an ideal option due to slower speeds. With this configuration, I successfully backed up my MacBook using Time Machine!

I understand the usual approach would be to turn off DHCP on the access points and let the main router handle IP distribution. However, I wanted to use the DHCP from my Google WiFi system, which I prefer for managing my network. So, instead of turning off the DHCP on the access points, I decided to disable the DHCP on the main router (which is also the ONU provided by my ISP) and let Google WiFi handle all the IP assignments.

This way, my devices (including the NAS) are all on the same subnet created by Google WiFi, and I avoid any conflicts between the two routers. It’s working smoothly now, and my NAS is accessible from all devices through Time Machine as well.

Thank you for your response.

I was able to locate the “macbook pro.sparsebundle” file on the NAS, which indicates that the Time Machine backup folder was correctly created. However, this sparsebundle seems to have been created when the NAS was previously directly connected to Google WiFi via Ethernet.

Currently, my NAS is no longer directly connected to Google WiFi. Instead, it is connected to a common router that both my MacBook (via Google WiFi) and the NAS share. Despite being able to connect to the NAS through SMB using its IP address, Time Machine still fails to find the backup disk.

Could the fact that this sparsebundle was created under a previous configuration be causing the current issue? If so, what would be the best way to resolve this and continue using Time Machine for backups with my current network setup?

Thank you again for your assistance.

I had previously set up the Time Machine service on my Synology NAS, and at that time, I was able to back up my Mac without any issues. The Time Machine service was running correctly on the NAS, and everything worked smoothly in my previous configuration.

However, after changing my network setup (with the NAS now connected to a common router, and my MacBook connected via Google WiFi), I’m facing issues where Time Machine cannot find the backup disk, even though I can still access the NAS via SMB and see the sparsebundle file.

Could there be any other configuration or setting that might have been affected by this network change, despite the Time Machine service having worked properly before?

I understand that Google WiFi may be causing issues with the connection to the Time Machine drive. However, I would prefer to avoid changing my WiFi setup if possible, as it would be quite disruptive. I’ve been able to successfully connect to the NAS via SMB and can even see the Time Machine backup sparsebundle file.

Since Time Machine was working correctly in the past with my current NAS setup, I’m wondering if there might be a network configuration issue or another setting that could be adjusted before resorting to replacing the WiFi access point.

Do you have any recommendations for troubleshooting the existing network setup with Google WiFi?