Error connecting with Duplicate Desktop: no virtual SCDisplay available (target=4, baseline=[3], available= [3], online= [3, 4])

[khemrajani]

Unable to connect to my iMac from two different machines, same error:
nessun SCDisplay virtuale disponibile (target=28, baseline=[1], disponibili=[1], online=[1, 28])
(except the target value, that is different between the machines)

Extended Display works and I can even manually change the Display settings to make the remote monitor the main, but I can't connect with Duplicate.

Using the v2.0 release downloads (First time user; never installed the earlier builds so unable to say whether this would've worked before.)

Senders:
Macbook Air M2 running Tahoe, 26.5
Mac mini M4 running Tahoe, 26.5

Receiver:
iMac 2017 running Sonoma 14.8.7 with OCLP

On both Senders, I'm able to see the Mirror in System Settings\Displays but then it eventually disappears, and then I see that error in the client.
On the Receiver, I see the Sender connected and "profile sent" before it produces that error.

Stuff I've done:
For the Sender machines, I had an error running it and used the xattr command. I've given the app the required permissions and rebooted a bunch of times. I installed homebrew on the receiver and ffmpeg and sdl2 as suggested on the reddit thread.

Tried with two different cables as well, both test above 10GBPS. Tried different TB ports on all the machines.

Any suggestions on what I might be doing wrong?

(As an aside, I use Hammerspoon to automate tasks on my machine. If there was a CLI version of this, I could likely just automate switching the display settings after Extend and that would be good enough.)

[ThomasWaldmann]

Note: I translated the italian error msg recently, so it will be english with current code.
What's a bit special for this error is that it is catched at another place in the code and then a string comparison is done for that error msg.

When practically testing, I always used extended display mode, so I never had this error.

[khemrajani]

Just tried with 2.0.1 and same issue BUT!

The error is now in English: no virtual SCDisplay available (target=4, baseline=[3], available= [3], online= [3, 4])

AND! Extended desktop still works with 5K now totally usable with the performance updates, so that's awesome.

[ThomasWaldmann]

@khemrajani can you try the patch from #53 (totally untested)?

Also, please update issue title with the english error msg.

[ThomasWaldmann]

Tested "duplicate" mode:

I first had "extended" configured and running (in the app as well as in macOS settings -> displays).

Then switched to "duplicate" in the app and connected: the display was still extending my desktop. After I switched to "mirror built-in display" in macOS settings also, it worked as expected.

[ThomasWaldmann]

Did you get it working?

If not, try:

• removing targetbridge from macOS screen permission (click "-").
• then add it again, click "+" and select the correct sender app you will run later.
• retry running the sender

[khemrajani]

Tested it with that bug fix and it works. I can connect instantly with Duplicate Display.

Sorry, took me a bit as I had to setup a build env on the receiver imac.