Game crashes after: "Error: Could not find or load main class net.minecraft.client.main.Main"

I had been playing no problem in Minecraft 1.14, and after spending some time off the game, I wanted to come back for the 1.15, but this "Error: Could not find or load main class net.minecraft.client.main.Main" message keeps poping up in the command line every time I try to play.

I've cleanly uninstalled and reinstalled Minecraft, Java (32, 64 bits, and the SDK) and my graphic's card drivers. I've updated Windows 10, used Jarfix, scanned the registries for any errors... but nothing works.

Furthermore, I've tried the 1.15 update, the original 1.14 that previously worked, the lastest snapshot and the 1.0 version.

In the installations menu, I've tried the automatic setting and to set the directories manually.

Does anyone have a clue on how to solve this issue?