Firewall is blocking Screen Sharing

I have been having this same issue as well when I purchased my MacBook-M1 last year and found I could not connect to it via Screen Sharing from my iMac (Intel). I found it strange because I could still Screen Share connect to my daughters MacBook i3-Intel with no issues and the Firewall turned on with the settings as previously stated above.

I also worked with Apple Support, got a case#, and provided many diagnostic data dumps for engineers to look at.. but to no avail.

Just a few weeks ago, I traded in my MacBook-M1 for the new MacBook-M2. I proceeded to use the Migration Wizard to copy all of my data and settings over, but still I am unable to Screen Share from my iMac unless I disable the firewall completely.

On another interesting note, my son got a new MacBook-M1 to get ready for the new school year, and while helping him set it up, I was able to Screen Share from my iMac with no issues and all of the Firewall settings configured as normal.

This leads me to believe that there was some firewall configuration setting that was migrated from my MacBook-M1 to my new MacBook-M2 that continues to prevent Screen Sharing from working with standard firewall configurations enabled.

I'm wondering if perhaps there was any way to reset the firewall configuration on my MacBook-M2 to factory settings?

That unfortunately seems to be the only thing that I can think of, other than completely restoring MacOS to factory settings.

@Captain-Mac, that's very disappointing to hear and I can attest to the same.

Another interesting find came from this thread:

https://origin-discussions2-us-dr-prz.apple.com/en/thread/253655805

I discovered that "Share Screen" seems to work when I disable "FileVault" while keeping the "Firewall" enabled. But who wants to compromise either, when we didn't have to worry about this issue before..?

Seems like an odd coding somewhere with the firewall or the OS.

Captain-Mac wrote:

When I turn off the built-in software firewall, Screen Sharing works.

If you are behind a router on your own Network—I would leave the macOS built-in firewall off, there is no need for it.

Captian-Mac: Thank you for the post! I think Apple introduced this problem in 12.4. I have an M1 mini I use as a media server for Apple TV (the hardware device, not the App). Screen sharing worked just fine Intel to Apple Silicon until 12.4. Strangely, screen sharing still works just fine, with Firewall on, Intel to Intel with 12.4. I also tried Silicon to Silicon, no joy. An nmap port scan shows port 5900 (vnc) as filtered on Silicon macs, but open for Intel Macs. I have no idea what ‘filtered’ means.

Hopefully, someone from Apple will find our posts useful in fixing the problem, assuming someone from Apple reads anything out here considering all of the garbage.

My M1 mini is headless (no KB, mouse, or monitor) making a real hassle to turn the firewall off.

Thanks again for your post.

Captain-Mac wrote:

That is a work around. I don’t want a work around. I want Apple to fix this bug so I don’t have to choose between leaving the firewall on or screen sharing.

Who said work a round...

Your router has a built in Firewall, you do not need two Firewalls on your own Network it can lead to interferences— you do not answer that question...

Take up the issue with Apple—

Call Customer Support  (800) MY–APPLE (800–692–7753)

or on line  Apple Support

submit your Apple Feedback http://www.apple.com/feedback 

I have a question. Let’s assume the firewall was working as you expect. Could you then describe the function of the firewall?

Captain-Mac wrote:

It's not working as expected.

What if it were? What would it do then?