Launcher VS PrismLauncher

If you cannot - https://github.com/MultiMC/Launcher/wiki/Unsupported-Intel-GPUs

MultiMC

maybe : https://github.com/MultiMC/Launcher/issues/41

Here is a link to Modloader for MCb173. It needs adding directly into the minecraft.jar file, however if you use a launcher like MultiMC, which you can find here: https://multimc.org/ then there is an option to 'add to minecraft jar file' which does the same thing.

I used to have this issue lots, and it was due to my internet being too restrictive. The Minecraft Launcher was refusing to open, and I fixed it by messing with the restrictions until it worked. Hopefully this helps :) if all else fails of course, try just reinstalling it! I’m sure that all your config files don’t get affected by reinstalling it, but just in case make a backup. And if all ELSE ELSE fails, you could switch to a completely different launcher, like MultiMC! Good luck!

If you are willing to try out the launcher - MultiMC which you can find here (there is a Mac option available) : https://multimc.org/ then I have put together an MCb173 pack that has been made for MultiMC. You just use the 'import from zip' option.

Download MultiMC from their official site https://multimc.org/

Others than that, if you insist, you can take a look at the launcher which u/reginakinhi provided or find others on the internet (GitHub for example). Since PrismLauncher is written in C++, and if you are not familiar with it, you should see other launcher as well. Or else https://github.com/MultiMC/Launcher is an alternate.

The best way to experience beta 173 is to play beta 173, and perhaps add some mods to it a little later. One of the better launchers to use for old versions and for playing modded is to use the MultiMC launcher which you can find here: https://multimc.org/

This will only assist if you are using MultiMC as your Minecraft launcher as it is a MultiMC instance which you can use the 'import from zip' option. MultiMC can be found here: https://multimc.org/ It includes IC2 1337 with several add-on mods which have also been back-ported to work with it, such as the Thermometer, Advanced machines, etc. You can disable the add-ons you do not wish included. There is also buildcraft and redpower added as well.

Change meta server to https://meta.prismlauncher.org/v1/ and MSA client id to c36a9fb6-4f2a-41ff-90bd-ae7cc92031eb in settings to keep using PolyMC. Both of these are by the main contributors that now moved to https://github.com/PlaceholderMC/PrismLauncher.

The falsely banned devs of PolyMC have created a new Launcher and are working hard to push a stable release right now (Github - Discord)

there's one on the prism launcher github https://github.com/PlaceholderMC/PrismLauncher

It's completely unrelated to PolyMC, but the safe fork from PolyMC's last "safe" code state is being worked on under the name "Prism Launcher" (initially called "PlaceholderMC").

From what I know, PolyMC and other launchers pull libraries needed to run the game when first setting up new instances and also periodically update those. Even if you don't update PolyMC, these libraries could be updated by the owner, replaced with versions that contain malicious code. If you want to keep using it, but be safe just in case, this issue contains a screenshot showing how to replace the metadata server, including a working alternative by the old contributors now working on the fork called Prism Launcher.