Same issue as Jakub, I would add ScreenSaver settings to that list too if possible. @RudoBaker did you report the feedback yet ?

This may be unrelated but I had some users report very high CPU usage starting with late 10.15 versions when I draw text using CALayer on retina. The bug doesn't happen on every single machine, I can't reproduce it on my Late 2015 iMac for example. I ended up adding a switch in my screensaver (Aerial) for high resolution text because of that. To directly answer your question, the way I fixed it is by rasterizing the layer I'm drawing, using this : nLayer.shouldRasterize = true https://developer.apple.com/documentation/quartzcore/calayer/1410905-shouldrasterize Do you see the high CPU usage in app mode too ? You may be able to file a feedback so they can track this down, as it's a huge regression and I still to this day have no idea exactly why it doesn't affect everyone.

So those graphics errors, in general, tend to pop up with other screensavers, so I don't think they are your issue. But I did try Mosaic here and it also hangs, after some digging I found this : erreur 14:30:03.837445+0100 accountsd "Cannot check access to a private account type: com.apple.account.AppleAccount" erreur 14:30:03.838207+0100 accountsd "Client (<private>) attempted to access restricted account type: com.apple.account.AppleAccount" erreur 14:30:03.838244+0100 accountsd Unentitled access by client 'iLifeSlideshows' (selector: <private>) erreur 14:30:03.838387+0100 iLifeSlideshows "Error returned from daemon: Error Domain=com.apple.accounts Code=7" Looks like they may have forgotten to set some permissions. This is on 11.2 (20D5042d) here. iLife-Slideshow is the wrapper for some of the old Apple screensavers with special permissions, but they may have missed some I guess. I'd suggest you file a feedback.

I can confirm that @Tempers solution worked for me ! I opened another project and my crashing project afterwards, and that works... I guess that's a good workaround in the meantime, thanks a lot.

Just to add some feedback, I've also hit that issue with macOS 11 Beta 10 and Xcode 12.2 beta 2 (I hadn't updated to beta3 yet). So It may not be just an Xcode 12.2 beta 3 thing.

FYI, reverting to Xcode beta2 lets you compile again (as the SDK is bundled with the xcode build), I filed a radar, guess we'll see.

Can confirm, same issue here on my project that worked fine with previous Xcode builds : /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.0.sdk/usr/lib/swift/AVFoundation.swiftmodule/arm64e-apple-macos.swiftinterface:1:1: Failed to build module 'AVFoundation' from its module interface; the compiler that produced it, 'Apple Swift version 5.3 (swiftlang-1200.2.22.2 clang-1200.0.25.1)', may have used features that aren't supported by this compiler, 'Apple Swift version 5.3 (swiftlang-1200.0.22.4 clang-1200.0.25.1)' Looks like a problem with the SDK, hopefully we'll get a fix soon.

@jbwils short answser, as of right now, not possible on Catalina and Big Sur, this may change soon though. Longer answer, Apple introduced in Catalina a new Sandboxing mechanism for the old fashioned plugin architecture. Screen savers (which are still plugins) are limited by the entitlements of legacyScreenSaver.appex, which doesn't include raw access to keyboard and mouse. Apple started moving its screen savers to an app extension format, but as of right now there's no extension target in Xcode 12 beta 1 to make screen savers. Hopefully this will come in a later seed and then, you'd be able (in theory) to do what you want by giving your own entitlements.

Yep, it doesn't show on the simulator in beta1, you have to run it on device. There are a few other issues that happen in simulator and not on device so I'd recommend you go this way to save some time.

See this thread here, you need to do it on device as the simulator is bugged : https://developer.apple.com/forums/thread/650831

Understood on the first point. Some form of communications about the changes that happened with no announcement nor documentation would have been appreciated, though. To this day the changes are still not documented anywhere (and new subtle bugs get reported to me often by users, and I'm not sure what to do about them, except filling radars with no feedback). I definitely understand screen savers are low priority but it's still a tiny bit frustrating 😉 I'll give it a shot on the second issue when I have a second.Thanks for your time.

Hi @eskimo !If I may jump in, you mentionned this :"The current screen saver architecture relies on an old plug-in model, one that Apple is working to eliminate across our systems because it has fundamental limitations."I definitely agree about those issues and will most definitely welcome the new API, but in the meantime we're in a weird space right now with screen savers on Catalina. Apple started moving some (most) of it's own screensavers behind a new .appex format that, to this day, is still unavailable to 3rd parties with no guidance on when (to be honest, I started wondering if it's not an "if" instead of a "when") it will be available. I have to say your message gives me hope that there will be a new API released at some point !In the meantime, the legacyScreenSaver.appex workaround has many bugs (I filled many radars) like always responding with the preview flag to true on init, or randomly resizing the main screen saver view to the size of the preview. After some time, I've managed to workaround those.And while many features are now understandably gated by the entitlements inherited from legacyScreenSaver (for example, in Aerial, I had an option allowing users to skip a video by pressing the right arrow key, this is no longer possible) and cause an inconvenience, my biggest concern is that I'm no longer able to provide an auto update mechanism because of the sandboxing restrictions (I used Sparkle, neither the 1.x nor the 2.x branch work, being denied either because of a quarantine issue when copying the auto updater, or an elevation privilege when trying to use xpc in the 2.x branch).Is there any chance we could get guidance on if we can expect the new api some day ?Second question if I may, you mention this in the post you refered to :"Old school plug-ins must use the system’s Swift runtime, meaning they must have a deployment target of macOS 10.14.4 or later."I currently still do it the old fashion way, as I still support older OSes with Aerial. There are two side effects I know of with Swift screensavers linked this way :- if you have two of them, you won't be able to switch from one to the other (as they will likely not use the same library) and get this error : "You cannot use the Aerial screen saver with this version of macOS."- if you try updating a swift screensaver without closing System Preferences first, the new version will get "partially loaded" (my limited understanding, either the code or the nib isn't reloaded, causing a crash).I would guess using system's Swift fix the first issue, do you happen to know if it would fix the second in a screensaver ?I want to thank you in general for your posts in this forum that, more than once, provided some great feedback that helped me figure some things out. And while I definitely understand that you may not able to provide any guidance here, any word would be greatly appreciated!