I play Minecraft on a Mac, and when I press the 'play' button on the Minecraft Launcher, it loads about halfway saying 'preparing' before opening Minecraft then shutting it. The launcher then comes up with a pop-up saying 'ERROR. Game crashed. An unexpected issue occurred and the game has crashed. We're sorry for the inconvenience.' I went to settings and clicked the 'open output log when games start' button and pressed 'play' again. I updated my Java to the most recent version before opening up the game and before that Minecraft was launching and working fine, so I don't know if it has to do with that. I just launched my game with the latest release of Minecraft (1.16.2) and it loaded fine, so it's only not working for me on forge (1.16.1-forge-32.0.107 on my launcher), which is what I use for all my worlds.

Here is what came up on the Minecraft game output (I have also attached screenshots of my screen):

 
20:44:29.908
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1612)
20:44:29.909
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
20:44:29.910
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
20:44:29.910
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
20:44:29.911
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
20:44:29.911
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
20:44:29.912
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at cpw.mods.modlauncher.TransformationServicesHandler.runScanningTransformationServices(TransformationServicesHandler.java:116)
20:44:29.913
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at cpw.mods.modlauncher.TransformationServicesHandler.initializeTransformationServices(TransformationServicesHandler.java:63)
20:44:29.915
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at cpw.mods.modlauncher.Launcher.run(Launcher.java:75)
20:44:29.915
[m[32m[20:44:29] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1052]: at cpw.mods.modlauncher.Launcher.main(Launcher.java:65)
20:44:29.973
[m
20:44:29.973
Process crashed with exit code 1