Cannot login using the new beta launcher

I have multiple accounts. When I first brought up the Beta Launcher, it did run, but then it wouldn't let me into my SMP server because of an Invalid Session. I was able to start a game the second time, still Invalid Session attempting to login on the SMP server. When I started the Beta launcher a third time, it wiped my account PW's and wanted me to relogin (that's good, that's expected and desirable). Unfortunately, now I have the same issue as described above where I am unable to login at all on the opening screen of the launcher. The correct email/pw gets an infinite "wait" box on both accounts. There's a third account I have, but I didn't bother with it, looking for a bug report first.

The "invalid session ID" may be the trigger, then when the accounts are reset to force relogging, the relogging infinite-wait fails.

I would strongly urge having "settings" accessible for, "Beta is doing bad things, can I roll back please?" I'll have to follow directions to wipe the launcher and restart on non-beta.

…
I deleted everything except C:\Program Files (x86)\Minecraft Launcher\MinecraftLauncher.exe and I allowed the launcher to do it's work. Unfortunately this ALSO cleared my custom sessions❓ , but the old launcher had no trouble at all accepting my login ID. I'll use the old until I hear of an update to the Beta. And yes, a hard "time-out" limit if the launcher can't figure things out would help a great deal in addition to the "back from Beta" button.

(Edited for clarity of what stage Beta Launcher vs. attempt at SMP server login I was when attempting)

Besides Andy Smith's excellent suggestion for having "Settings" accessible, the launcher should also time out after some fixed interval.

Same issue here. It started after updating the Minecraft Launcher for MacOS to version 426 (1).

Yep, I experienced the same issue when I accidentally opened two launcher instances (even though one didn't show up) and, as usual, it puts the second one into the login screen, and that's where the problem began. I think this only happens when the launcher forces you into the login screen.

I hae the same issue and have no clue on how to fix it if you know how please tell me In ENGLISH

Here's how to disable the beta launcher again:

If you switched to the beta launcher and can't log in, you can switch back by editing launcher_profiles.json in your minecraft folder. Change the "channel" field from "beta" to "release".

– Tweet by @unknown

Here's a guide on how to find your minecraft folder: Click me

[Mod] violine1101 - How do I edit launcher_profiles.json file on MacOS? I can find the file, but I have no way to view and edit the contents.

JSON can be opened and edited by any plain text editor.

If you need any further assistance with opting out of the beta launcher, please join the Community Support help chat. There are people in there that can help you.

Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki

When I open the JSON file in any text editor on MacOS is display a mess of characters and it’s not possible
To make the changes you mention. Please advise when Mojang will be fixing the issue.

@unknown, this sounds like either the MacOS editor, or your Minecraft installation is broken. As I already said, please join the Community Support help chat. There are people in there that can help you.

@[Mod] violine1101 ... THANK YOU very much! I was at my wits' end. sure hope the BETA installer update gets updated to work correctly, soon!!!