This is one of the common ways to fix an ailing Minecraft installation of various bugs is to simply re-install it. If you removing the launcher itself (the file you downloaded) however will not remove Minecraft. The steps below should work for most people.
Reinstalling Minecraft On Windows
- Navigate to your Application Data Folder: %AppData%
- Open .minecraft folder
- Copy out the saves folder to a different location
- Go back .minecraft folder
- Delete .minecraft folder or move to trash.
- Double click to Minecraft.exe file to re-download Minecraft
- Close Minecraft when you reach the title screen
- Copy the saves folder back into the new .minecraft folder. You can safely overwrite any data that’s currently in this folder
Reinstalling Minecraft On GNU/Linux
- Open a terminal
- Copy and Paste the following, one at a time, into the terminal to delete the current minecraft installation and retain the current saved worlds.
mv -v ~/.minecraft/saves /tmp/mc-save-tmp
Be careful, do not continue if your terminal gives you an error. The next command deletes your minecraft folder so if the prior command did not work all your hard work would be lost!
rm -vr ~/.minecraft/*
mv -v /tmp/mc-save-tmp ~/.minecraft/saves
- Start Minecraft like you normally would. Your saves should be intact and the Minecraft client will re-download itself for you.
Alternatively, open up your Home folder and press Ctrl+H. This shows all hidden files and folders. Navigate down to .minecraft. From here, you can work in essentially the same way as outlined in the instructions for Windows above.
Reinstalling Minecraft On Mac OS X:
- Open a Finder window
- Click the Go Menu item and Click Go to Folder
- Type ~/Library/Application Support/minecraft into the text field and click Go
- Drag the saves folder to your desktop
- Drag everything else in the minecraft folder to the trash
- Drag the saves folder back into the minecraft folder
- Close the Finder window and launch the Minecraft App just like you would normally.