Screen Sharing on 10.15.0

[macattackjack]

I just updated to Catalina from 10.14.6

I use screen sharing with a Mac that runs 10.13.2. It has worked well. Testing the Mac with Catalina, the other Mac has frozen two times. I'm not sure if it's just a random thing, except it's never done this before.

I thought I read something about Catalina having some sort of bug with screen sharing with older Mac OS's, but can't find any links.

Any thoughts? I am testing the computer now without screen sharing, and then see what happens with it on.

Thanks in advance.

[macattackjack]

I figured it out.

Two things. First, the fact that the program froze was a semi fluke. Twice. But then I shut both computers down and shut off the peripherals completely, restarted both computers, and that problem went away. One has Catalina and the other has High Sierra 10.13.2.

I am using audio programs on both computers. Because (thank you Apple for a feature I didn't need) you can now drag and drop files from a Catalina computer using screen sharing to another computer, even one not using Catalina, Screen sharing is looking for any drives connected to the Catalina Mac and sending that data over the ethernet connection to the second computer.

I realized this because I was running audio and connected a USB3 external drive to the Catalina computer, and the other computer got an error saying the drive wasn't fast enough to keep up with the audio, and that perhaps it was a firewire drive that was too slow. There aren't any firewire drives.

AND as far as I can tell, there's no way to shut off that feature.

I am going to see if the older version will work on Catalina, and if so, what happens. While not a common situation, the increased bandwidth is a problem for me and could be for other audio apps and especially video apps. And certainly there are other audio apps that are pushing large amounts of audio through the network cards, and that could be a problem for them too.

[macattackjack]

Just transferred files, both directions

As far as the audio, I'm not sure what you mean, the audio application is putting up an hard disk read error window complaining the drive isn't fast enough. That has happened rarely, and to have it happen as soon as I put in an external drive is more than a coincidence. And to be clear, I plugged in the external USB3 drive on the master computer, NOT the computer running the audio application that generated the hard drive read error. So in other words, plugging in the external USB3 drive to the Catalina computer immediately caused the Audio Application on the High Sierra computer to complain its drive wasn't fast enough to play back the audio data from the hard disk. And actually now that I think about it, the USB3 drives show up with the firewire icon, and the error message referred to a firewire drive being a possible problem.

The two are definitely talking to each other about something, and it ain't good. As far as I can tell, there's no way to shut this off. Shutting off the shared clipboard does nothing. I was still able to transfer files desktop to desktop.

Blue screen is Catalina, purple is high Sierra. I transferred flamingos from another folder first to High Sierra, then back to Catalina, with clipboard on, then Floating Ice back and forth with the clipboard off.

I wonder if the Final Version of High Sierra would help this? the slave is on 10.13.2

This also makes me wonder if could it be the USB patches and how they're working with Catalina? These are the patches I am using. USB3 has been iffy on this machine. I have a PCIe card that, if I remember correctly, had a compatible OOB chip on it, whereas the USB on the x79 sabertooth only works if it's active when booting up, and was always temperamental. 

Again, none of this happened with Mojave and high Sierra.

            

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Of course, what I also noticed is that all times that the High Sierra Mac froze, I used a saved alias for the screen sharing from the Catalina computer that was copied over from Mojave. This is the second time I'm testing the screen sharing where I accessed it from the "connect to server" menu, and it hasn't frozen.

That would be weird. And stupid.

Edited October 15, 2019 by Allan
<Code>

[macattackjack]

As you recall, is there any weirdness using the 10.13.6 combo update

or anything weird going from 10.15.0 to the update?

[macattackjack]

actually, which update for 15 are you talking about, the supplemental one, or the beta 10.15.1? I just got the notification for the supplemental one (even though updates are turned off. Interesting)

[macattackjack]

Okay I have isolated this more

1. I updated the slave computer to 10.13.6. I first updated a backup drive and the update was weird. But I'll spare the details. When I updated on my primary drive, all went well.
2. The master computer was running Mojave 10.14.6. I updated to 10.15.0 from Mojave, and then I downloaded the update directly from Apple and installed it. It is now running the official release of the 10.15.1 update. No Betas have ever touched this computer, and they never shall.

Here's what's causing part of the problem.

I had both computers on, the High Sierra slave and the Master running Mojave. I restarted the Master and booted into the Catalina Drive. I started screen sharing, tested it with the audio applications, and after a while, maybe 30 minutes, the slave froze.

I am thinking I updated to 10.13.6 for nothing, but, later, I shut down both computers. I leave them off for a bit. I restart both, Master booted into Catalina, and slave booted into High Sierra.

I tested them again, recording and playing back audio, then putting the master and slave in a loop, playing for a couple of hours, and it didn't freeze.

And just to be sure, leaving the slave on, I switched the Master back to the Mojave drive, and ran the same test, and the slave didn't freeze. So it's definitely Catalina causing the problem.

My assessment is that the Slave doesn't like something about switching from one OS to another.

Now this is fine, since once I commit to Catalina I won't be switching back and forth. I am not ready to do yet since some apps haven't been updated to be compatible with Catalina. But what about IT guys, who may be networking computers with different OS versions on them? If they are screen sharing with one computer that has Mojave, and then go to screen sharing with one that has Catalina, this could be a problem.

Again, I attribute this to the added functionality of being able to drag and drop files between computers in screen sharing. My guess is that the increased monitoring required, high level events, drive status, etc, is doing something bad, and my freezes from just plugging in a drive seem to point in that direction.