ExplodingBottle

Hello,

Here are the in-depth reproduction steps:

1. Install Minecraft Launcher for Minecraft Java Edition

2. Log in with your Microsoft/Mojang account

3. Go to configurations

4. Click New Configuration

5. Enter as name: Minecraft 1.8.9

6. Select the icon: Cake

7. Select version: 1.8.9

8. Go to JVM arguments: change -Xmx2G to -Xmx4G

9. Press Create

10. Navigate to Play Tab

11. Press the Play button

12. Check I understand risks

13. And press play

14. Wait for it to download the game...

15. Press quit game.

NOTE: Certains of these elements are certainly useless because I'm saying what I'm exactly doing.

And I notice that this bug is fixed in the last version, as it now downloads the x64 version instead of the x86 version !

Have a nice day.

That's not a parsing problem,

It's doing the same with a parameter only for x86 architecture.

The parameter -Xss1M should be included only on x86 architecture as showed by the rule:
            {
                "rules": [
                    {
                        "action": "allow",
                        "os": {
                            "arch": "x86"
                        }
                    }
                ],
                "value": "-Xss1M"
            }
 
[Info: 2021-05-23 17:05:10.6442246: ClientStarter.cpp(904)] Java argument:-Xss1M
But, In the log, we can see:

[Info: 2021-05-29 16:57:39.8812304: Common.cpp(41)] x64: true
So, the Launcher doesn't recognise correctly the system architecture !

So, the Launcher just don't use this value.

Hello,

As you can see in the log, I've deleted the library that was not using the correct architecture.

It looks that there is a problem while parsing.

 
"downloads": {
                "classifiers": {
                    "natives-osx": {
                        "path": "tv/twitch/twitch-platform/6.5/twitch-platform-6.5-natives-osx.jar",
                        "sha1": "5f9d1ee26257b3a33f0ca06fed335ef462af659f",
                        "size": 455359,
                        "url": "https://libraries.minecraft.net/tv/twitch/twitch-platform/6.5/twitch-platform-6.5-natives-osx.jar"
                    },
                    "natives-windows-32": {
                        "path": "tv/twitch/twitch-platform/6.5/twitch-platform-6.5-natives-windows-32.jar",
                        "sha1": "206c4ccaecdbcfd2a1631150c69a97bbc9c20c11",
                        "size": 474225,
                        "url": "https://libraries.minecraft.net/tv/twitch/twitch-platform/6.5/twitch-platform-6.5-natives-windows-32.jar"
                    },
                    "natives-windows-64": {
                        "path": "tv/twitch/twitch-platform/6.5/twitch-platform-6.5-natives-windows-64.jar",
                        "sha1": "9fdd0fd5aed0817063dcf95b69349a171f447ebd",
                        "size": 580098,
                        "url": "https://libraries.minecraft.net/tv/twitch/twitch-platform/6.5/twitch-platform-6.5-natives-windows-64.jar"
                    }
                }
            }
In this piece of manifest of Minecraft 1.8.9, we can see that there is three categories of downloads.
natives-osx, natives-windows-32 and natives-windows-64.
But the problem is: the launcher doesn't respects the platform, and choose to download natives-windows-32 instead of natives-windows-64.
 
I hope I have correctly answered your request.
Have a nice day.

Hello,

Can you browse to the folder where the Minecraft Launcher is installed,

Then right click on MinecraftLauncher.exe and properties.

Then go to the Compatibility tab,

Check if "Execute this program with compatibility mode" is checked.

If no, then reply,

If yes, uncheck that.

Have a nice end of day.