I need some help connecting two Macs. I have a late 2015 27" iMac and a new 2021 MBP M1 Max.

I would like to connect my iMac to my MBP to share files and the printer. I know I can do this over WiFi, but my photos, for example, are 300 GB and it seems sensible to have a permanent connection, if it is easy to set up.

I also have an Anker Apex 12-in-1 Thunderbolt 4 Dock port replicator which is working to drive 2 Ben 27" 4k monitors.

I would like it set up so that file transfers between the two computers use the wired connection, but internet activity from both computers uses the WiFi network.

Is this possible?

If so, please could you tell me exactly which cable I need to buy?

1 Answer 1


The maximum file transfer speed of the 2015 iMac is 20 Gbps through the Thunderbolt 2 ports. You can connect the two Macs to transfer at this speed by using Apple's Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter and Apple Thunderbolt Cable. (On the 2015 iMac, the ethernet port has a maximum speed of 1 Gbps and the USB ports have a maximum speed of 5 Gbps.)

The adaptor is listed as compatible with your MBP and the cable is listed as compatible with your iMac. Thunderbolt 4 is backward compatible with Thunderbolt 3.

Once connected, the connection will appear in the Network pane of the System Preferences application as a Thunderbolt Bridge. You can then use Connect to Server popup of the Finder Application to connect via smb. For example, if the iMac shows a IP address of, then enter smb:// as the server address in the popup window on the MBP. You will get a window showing the drives on the iMac.

  • Thank you, very helpful. Can I ensure that file transfers and other communication between the two computers occurs via Thunderbolt whilst internet occurs via WiFi. I have altered the network priority sequence to prioritise WiFi which is necessary for the internet to work, but will that not mean that file transfers also go via WiFi? Mar 27, 2022 at 8:41

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