The launcher appears to launch and finalize launching but immediately crashes with [quote] Exit Code 0 [unquote] due to cannot load net.minecraft.client.main.Main (as shown by the attachments).
P.S. I found it occuring on both 1.12.2 (previously-downloaded), 1.17.1 (newly-downlaoded) and 21w39a (tried both), suggesting that it’s potentially regardless of Minecraft version.

Relates to the other bajillion “Error Code 0” issues.