Workaround
Downgrading is not, was never, and will never be officially supported. You are advised to run older versions in separate directories. Otherwise, issues like this will occur.
To change directories, please read this guide.
If you need to use the same directory (not recommended, but provided for completeness):
Stop Minecraft
Navigate to
[.minecraft/|http://hopper.minecraft.net/help/guides/finding-minecraft-data-folder/]
Open
options.txt
with an editorSearch for the line
lang:xx_yy
(xx_yy = LanguageCode_CountryCode, e.g. en_us for English (US) )Change the lowercase CountryCode to uppercase, e.g. change
en_us
toen_US
Save the file
When launching Minecraft 1.5.2 or below in a folder that was previously used to start a recent version (e.g. 1.12), the game will crash on start:
java.lang.NullPointerException
at java.io.Reader.<init>(Unknown Source)
at java.io.InputStreamReader.<init>(Unknown Source)
at bp.a(SourceFile:64)
at bp.a(SourceFile:100)
at net.minecraft.client.Minecraft.a(SourceFile:252)
at avv.a(SourceFile:56)
at net.minecraft.client.Minecraft.run(SourceFile:507)
at java.lang.Thread.run(Unknown Source)
Steps to Reproduce:
Create a new profile using the latest version.
Launch it.
Close the game, and then change the version to 1.5.2 (or earlier).
Launch it.
Observe that the game crashes on start.
3. Watch it not even start up and crash.
Related issues
is duplicated by
relates to
Attachments
Comments


I'm sorry, but we cannot track issues that are related to very old modifications.
This is a technical support issue; this site is for bug reports only. For technical support please use the Mojang Support Center.

It is your job to deal with these kinds of problems, since the launcher can't literally launch versions prior to 1.5.2, so this is technically considered a launcher bug. The previous launcher worked perfectly with any older version, even back to Alpha, so there is no reason for it not to work with the new launcher (it's basically one of its' main features).
If this is really to be considered a new and improved launcher, then it should be able to do everything the previous one did, and nothing less.
This is not an issue related to an old version, this is an issue with a new launcher unable to startup the older versions, and it should be addressed immediately. Everything worked fine before and it just had to be screwed up.
I'm sure there's a simple fix to this problem, and it has something to do with the "id": "legacy" on the .json of older versions with the new launcher.

Please provide the crash report so we can further investigate this issue.

The launcher is unable to launch 1.5.2 anymore in order to show it crash (I wish I had saved a crash log from some days ago), so it doesn't create a crash log in my .minecraft of what happened. When I attempt to launch it, it just says "An unexpected issue occurred and the game has crashed. We're sorry for the inconvenience."
So the only information I can show is with the Output Log when I try to start it up. Everything is ok until this happens in the Output Log:
13:56:10 launcher Version does not support log configuration, will assume one plaintext entry per line
13:56:10 game fev 12, 2017 1:56:10 PM net.minecraft.launchwrapper.LogWrapper log
13:56:10 game INFO: Using tweak class name net.minecraft.launchwrapper.VanillaTweaker
13:56:11 game fev 12, 2017 1:56:11 PM net.minecraft.launchwrapper.LogWrapper log
13:56:11 game INFO: Launching wrapped minecraft
13:56:12 launcher Process closed with exit code -1073740791
This just shows how bad it is at the moment.. it's unable to even launch the game and crash xD

Duplicate of MC-112780, please follow the instructions on that ticket to solve your issue.
And I'm sorry for not correctly handling your request earlier.

Ok, now it's able to launch thanks to the nvidia driver fix. But it now crashes just like before I had installed the nvidia update. Here is the crash report (It says its probably modded, to which I guarantee it is not):
https://bugs.mojang.com/secure/attachment/133906/crash-2017-02-12_14.49.32-client.txt

You may need to reinstall the locally installed files that Minecraft puts into place. To do so, press your Windows+R keys, type in %AppData% at the dialog, and press Enter. In the window that appears, open the .minecraft directory, and delete everything except for the saves directory that you see therein. Then, try running Minecraft again.

Oh I forgot to mention that the crash happened on 1.5.2 and older versions, the latest one works just fine.

Please still try to redownload the game, there is a chance something didn't download correctly.

That's what I've tried countless times already, here is the new crash report:
https://bugs.mojang.com/secure/attachment/133918/crash-2017-02-12_16.39.46-client.txt
I'm really curious why the "id": on the .json file of every version before 1.5.2 (including 1.5.2) has been changed to "legacy" with this new launcher update. It's really nerve wracking because it's precisely the 1.5.2 version that I want to use. There needs to be a simple fix in order to play the older versions, it can't be that complicated.

Your crash report is a bug that was fixed one version later, in 1.6. Did it work fine on the old launcher?

Yes, the old launcher worked perfectly with every version available, including 1.5.2.

What Language do you currently have selected in your launcher?

I always use the standard language: English (US).

Sure, but in your options.txt
there may be the entry Language=en_us
whereas the old version expects there en_US
and crashes because en_us
!= en_US

Yes, there is an entry called lang:en_us in my options.txt, should I attempt to change it to en_US and launch 1.5.2 that way?

That simple entry actually enabled the game to launch now, but that still doesn't explain the change in the 1.5.2 (and older versions) .json file from "id": "1.5.2" to "id": "legacy", since that must have something to do with modded versions not showing up anymore.
And you can't say that it's not a Launcher issue, because as soon as I updated to the new one, the change I described earlier happened, and no modded versions would show up in the new Launcher's versions list, even though they've worked for years with the previous launcher.
I'm well aware the problem isn't just (probably) with the .json file, but this change needs to be addressed since things worked perfectly before, and I've seen other people unable to use modded versions of 1.5.2 with the new launcher.
Everyone has heard this one before, but "If it isn't broken, don't fix it", referring to the old launcher of course.

I would like to know the reason behind the change in the 1.5.2 (and older) .json files, which changed the "id": "1.5.2" into "id": "legacy".
After the new launcher and that changed, modded versions of 1.5.2 stopped being able to show up on the versions list (in the launcher), which is a huge issue.
I understand that older versions are no longer supported, but that's not the problem in hand, since before this new launcher, modded versions would work fine and show up when creating a new profile. If that issue can be solved, then this launcher would definitely be an upgrade, but now it's just useless for people that want to play older modded versions.

@unknown, please create a separate ticket about that "id:" thing (leave a reference to this ticket)

Invalid, because this ticket is MC-4947

I have something i wish to add. While using any launcher 1.6 or lower, attempting to connect to any server running 1.6 or lower causes me to receive "Bad Login".
This still occurs regardless if i made a new directory or not.

I've completely rewritten this report for searchability and accuracy (you're free to rant elsewhere, but the rant wasn't correct or relevant). If you haven't already, do feel free to create a separate issue regarding the "Legacy" message.

I have tried this I'm currentl using version 1.16.3 and it still says that the game crashed while trying to use 1.8.9.
I'm using Linux Ubuntu 20.04.1

Please read the moderator note Batu.

Relates to MCL-21801.It also happens in 13w16a to 13w26a.

Can confirm it crashes. Still trying to find out how to safely get the Err422 and where it is lol

mods dont show the full thing of what Error 422 was like (not as in Minecraft people but as in configurations)

Minecraft, if you're hearing this, will you add the Error422 Version please? i REALLY REALLY want to play it and see if i can find this so called "Err422".
If it isn't real like giant alex and the others then sigh

its an easy fix. well, not really a "fix", but a workaround! just create a new file for the worlds to be stored in, because (from my understanding) the reason its crashing is because the old world format dosent work in the same folder as new ones!