[Solved] MacBook Air and iMac no longer connect after macOS Catalina update

iMac and MacBook Air lost connection error

A few weeks ago my reader Alfred wrote to me that he has had problems connecting his MacBook Air to macOS Catalina since he updated his MacBook Air to his iMac. So far he has clicked on the iMac in the Finder and was then able to connect to the big Mac without any problems. The iMac is still displayed in the Finder, but clicking the iMac icon will result in the error message "Connection failed".

If he goes instead via the Finder menu "Go" and selects the item "Connect to server", he can establish a connection to the iMac after entering the IP address. Most of the time, restarting the MacBook Air also helps if the link to the iMac is established immediately afterwards. Understandably, however, this is not a permanent solution.

Its macs and operating system versions

Alfred owns three Macs that run the following macOS versions:

  • MacBook Air (macOS Catalina)
  • iMac (macOS Mojave)
  • Mac Mini (macOS Catalina)

The solution to disable AFP file sharing

Unfortunately, after his description of the error, I was not aware of any other case and I have not been able to research a report with appropriate instructions in forums. After a good three weeks, Alfred has now found the solution himself:

He had disabled file sharing via AFP (AFP stands for Apple Filing Protocol) under Mojave on all Macs. Back then everything was still going. Then he updated two Macs to macOS Catalina and the AFP sharing seems to be activated by default, which led to the behavior described above.

He's got over now System Settings> Sharing> File Sharing> Options The checkmark next to "Share files and folders via AFP" has been removed (on all Macs!) and now the computers can connect to each other again. Instead of AFP, you should use the SMB protocol, which can also be set under the advanced options.

Under System Settings> Sharing> File Sharing you can find the "Options" button, which you can use to select the advanced settings for sharing files and folders.

Under System Settings> Sharing> File Sharing you can find the "Options" button, which you can use to select the advanced settings for sharing files and folders.

 

In the advanced options of file sharing, the AFP protocol should be deactivated and SMB should be activated instead.

In the advanced options of file sharing, the AFP protocol should be deactivated and SMB should be activated instead.

Apple support document on file sharing

For the sake of completeness, I would like to briefly refer to the Apple support document indicate that they have put online for file sharing. There is an interesting note in it:

It is not possible to share Apple File System (APFS) volumes using AFP (Apple Filing Protocol).

So it should actually be clear that AFP no longer works for the startup volume from macOS Mojave, because this version of macOS - just like Catalina - requires that the volume be formatted as APFS. Why an automatic activation of AFP after the Catalina update took place with my reader is inexplicable to me (see also macOS Catalina collective article on solutions and problems).

But despite everything: Thanks to Alfred for the feedback, which might help one or the other Mac user with troubleshooting.

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2 comments

  1. pretzel monster says:

    Hi, that actually works (at least after reboot).

    Thank you!

  2. Uwe says:

    Excellent! Always looking for a solution. A restart was always necessary to connect my iMac and the Macbook. Now it finally works again!

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