It's starting to irritate me that I have to download the 1.12.2 update every time I go to open up Minecraft. I don't know why it is, but it's only this update, and only this computer that I'm using. The computer worked fine with every other update before this, but now isn't. Why do I have to do this? Is there a solution?
Provided what you say is true.
Completely uninstall Minecraft used a registry cleaner like ccleaner to make sure the computer is clean.
also 1.12.2 exclusively runs on java 8. Make sure you have updated to Java 8 latest version.
Get a decent Minecraft launcher like the TwitchApp.