I am using the latest build of SheepShaver (September 2019) in the latest version of Mojave 10.14.6, on a 27 inch 2019 iMac Core i9. It is a fresh install of Mojave and SheepShaver is running in a fresh admin account to rule out any system issues.

SheepShaver will run fine in any windowed mode, but when I switch to full screen (i.e. using the "dga" rather than "win" setting in the preferences file) I get a black screen with a spinning beach ball. Switching back to windowed mode fixes the problem. Multiple resolutions work fine in windowed mode. Any resolutions in full screen mode lead to the black screen. I have to force quit SheepShaver each time this happens.

I have tried modifying a whole range of settings in the preferences, used different ROM files, MacOS system versions etc. ; all of which indicate the windowed vs. fullscreen mode as being the source of the issue.

No such problems here, but I do not have a Retina screen.

Does the window mode / full-screen mode toggle (control-return) work as intended after starting in window mode?

No problem here with a MacBook Pro with a Retina screen under Mojave. Full-screen works when set in the Preferences and when toggled from windowed mode.

Possibly SheepShaver 2.5 simply can't handle the 5120‑by‑2880 resolution. Have you tried reducing the display resolution (temporarily) and then running SheepShaver? Or try setting scale_integer and scale_nearest to true in the prefs. See this thread:

viewtopic.php?f=20&t=9998

When launching in windowed mode, switching to (and from) full screen with control-return still works.

This really has me completely and utterly stumped. I have been able to reproduce the behavior on my 5k iMac (2019 Core i9), another 5k iMac (2015 Core i5), and my old 2013 iMac with 2560x1440 resolution.

It occurs in fresh installs of Mojave, and a fresh install of Catalina Beta 8. (i.e. I have not done any non-standard stuff to these systems)

I also ruled out my specific configurations of SheepShaver as the source of the problem by downloading and configuring the September 2019 build from scratch, including fresh preferences, disk images, ROM files etc.

I have also been able to reproduce the problem when using emendelson's SheepShaver wrappers.

Scaling settings have no impact on this issue, nor does any other setting as far as I can tell.

All I can say for certain, is that this problem never occurred before Mojave 10.14.5 or higher.

In High Sierra the problem does not occur.

Once last thing - to make it even harder to trouble shoot, sometimes SheepShaver *will* start up normally in full screen mode. But then I might close it, come back half an hour later and it will revert to the black screen problem. I also see the problem occurring immediately after a cold boot.

I am out of ideas for now.

Thanks for investigating the issue this thoroughly! It is indeed a mystery, especially as you are the only one reporting the issue and on different machines.

Just a hunch: I wonder if settings in macOS for Mission Control could be involved.

I tried turning of all Mission Control options and rebooting, but that unfortunately had no effect.

Just to reinforce the point that my system is not to blame, I formatted an external SSD drive and plugged it into my 2019 iMac 5k. I then installed Mojave 10.14.5, and as soon as it booted up I immediately downloaded emendelson's SheepShaver wrapper. I then went into the package contents and edited the preferences file to 'dga' instead of 'win'. All other default settings were left in place.

I launched the app and then it immediately went to the black screen with beachball. It stayed on the black screen until I used force quit. After 4 or 5 launches it did come up once in full screen with the flashing disk icon. But it does not hold and goes back to black screen in future launches.

My 2019 iMac is a 3.6ghz i9, Vega 48. I do not think graphic card issues come into play because my old iMac has an Nvidia card and it has the same problem in Mojave.

I can only gather at this stage that Apple has introduced something starting from Mojave 10.14.5 (and continuing into Catalina) that produces some kind of instability in full screen mode for SheepShaver.

Based on the comments of others, it does not appear to affect MacBook Pros. It seems common to iMacs, but it does not seem to be specifically an issue with retina screens, as the testing on my old iMac confirms.

The issue does not occur on my iMac (21.5-inch, Late 2013) running macOS 10.14.6.

Yes, I do not think it would affect all iMacs, but clearly it affects some.

At this stage I will park the issue until I upgrade to the final release of Catalina.

Unfortunately, I am getting the same results in Catalina.

I am wondering if this is an issue with updated video card drivers in Mojave 10.14.5 and up. I am otherwise at a loss to understand why the issue would only manifest itself in later releases of Mojave, and seemingly only on certain iMac models with 27 inch screens.

I wonder if manually compiling the kanjitalk build in Catalina could help. I might give that a go.

I think I asked this previously, but does SheepShaver have any dependence on SDL? If so, can I try compiling with an earlier version?

I should add, when the freeze up occurs, there is absolutely nothing showing up in the console logs. It is as if the process is not running at all. I only see the resulting console log entry when I force quit SheepShaver.

All SheepShaver version 2.5 builds, built from kanjitalk755 source, depend on SDL2. The application packages of my builds contain SDL2.framework version 2.0.9. Version 2.0.8 appeared buggy in SheepShaver. I do not know which SDL2 version emendelson used. Version 2.0.10 is the latest stable version.

The version I have has file dates of October 2018. That seems to mean 2.0.9. I'll update it to 2.0.10 and recompile my versions. Is there an easy way to be certain which version I'm using?

October 2018 files are indeed version 2.0.9.

I will post your SDL2 2.0.10 build shortly. See if that one solves the problem almeath encounters.

I keep the downloaded .dmg files for reference.

Done. viewtopic.php?f=20&t=7360

Thanks for the newest build. I wish I could say it fixed the problem, but unfortunately the black screen freeze up is still happening, in both Mojave and Catalina (Catalina being freshly installed from scratch just yesterday).

As previously mentioned, my files and configs are fine, but to remove all doubt I am performing tests with emendelson's wrapper. I know the wrapper is not yet specifically updated for Catalina, but I placed the latest 2.5 build inside the wrapper and manually launched "MacOS.sheepvm" but still experienced the same freezes as with the main SheepShaver app on my Mojave install. Just as in Mohave, launching in windowed mode seems to avoid the problem.

I am going to proceed with attempting my own builds from github, both in Mojave and Catalina. I might try building with the latest dev build of SDL 2 as well.

Note that since July 2018 builds by emendelson and by me are from github.com/kanjitalk755/macemu not from github.com/cebix/macemu .

Yes, I was aware of that, thanks for confirming. As I mentioned in my edited post above, I do not know if using a cutting edge dev build of SDL2 could help, but I will give it a try.

So I tried building from the kanjitalk755 branch with SDL 2.0.7 through 2.0.10, but none of these fixed the problem.

2.0.5 is too old and fails to build, as does the mercurial 2.0.11 dev build of SDL2.

So I am back to square one at this stage.

I can launch in fullscreen mode perhaps 50% of the time, if I am lucky. So frustrating.

Strange also. One would expect something like this to happen always or never, not sometimes.

Also noteworthy:
You wrote that it happens on your Late 2013 27-inch Intel Core i5 iMac.
But it does not happen on my very similar Late 2013 21.5-inch Intel Core i5 iMac.

Could a different graphic card play a role? Mine is a NVIDIA GeForce GT 750M.

I am also experiencing this problem in the final release of Catalina and Version 2.5, 11 October 2019 build of SheepShaver on a MacBook Pro (13-inch, 2016, Four Thunderbolt 3 Ports). SheepShaver's possible relevant preference settings:

screen dga/1440/900
windowmodes 0
screenmodes 0

Yes, it is very strange, because when it happened on my older iMac I just assumed it was bugs introduced by Apple in their Nvidia graphics card drivers. It is well known that Apple does not like Nvidia and has gone out of their way to ensure their cards are not properly supported anymore. However, I was very surprised when the same thing happened on my 2019 iMac with AMD graphics. I might have to wait and see if anyone else with newer Macs reports similar problems. I saw another report in the forums of black screen and pinwheels in Catalina, but it could be entirely unrelated.

Tested on a Mac mini (Late 2012) and experienced the same symptom. I will note that this was not a clean setup, but a copy of the same setup from my MacBook Pro (13-inch, 2016, Four Thunderbolt 3 Ports) which is also experiencing this symptom.

1440x900 is one of the scaled resolutions available on your MacBook Pro. What happens if you use a different setting (e.g., dga/1400/840)?

Editing pref file to dga/1400/840 has no effect. SheepShaver still stops responding immediately upon launch. Changing it to win/1440/900 will result in a successful launch and I can use Control Return to toggle between Window and Fullscreen mode.

Not a developer and can't even pretend to be one, a quick google search on how to debug a Mac app suggested running sudo dtruss -n SheepShaver in Terminal. The error below repeated every so often.

dtrace: error on enabled probe ID 2186 (ID 165: syscall::read:return): invalid kernel access in action #13 at DIF offset 68