After version 1.6 the minecraft launch system has changed so that you have to get a launcher and run it with some complicated commands. Every launch with this launcher now checks for new natives and libraries like lwjgl, and this means that every time you run the game you have to wait about 30-40 seconds for this job to finish.

Is there any way to run minecraft without checking for new files?

1 Answer 1


NOTE: This is a workaround, not an official way to do it.

I've noticed that on modded minecraft versions, the launcher just basically shrugs and skips the library checks. Here's how to make a version a "modded" version without it actually being modded.

  1. First, browse to your .minecraft/versions directory. If you're using Windows, it's under %APPDATA%\roaming\.minecraft. You can get to it by opening Run and then typing in %APPDATA%\roaming\.minecraft and then pressing enter. If you're using iOS, I think it's under Library/Application Data/minecraft. If you're using a Unix-based operating system, it's under ~/.minecraft/.
  2. Copy the folder of the version you want to skip libraries on to the current directory. It should come out as something like "1.7.10 (copy)". Rename it to (say) "1.7.10A".
  3. Go in the folder. You should see a jar file and a JSON file. Rename the jar file to what you renamed the folder to, exactly, but with its original extension. Same with the json file.
  4. Open the JSON file. You should see "id": "something". Rename the something inside the original quotation marks with what you renamed the folder to.
  5. Minecraft should not check the libraries, as it does not recognize the ID of the version as one of its remote versions. Or so I think.

I believe this works because of some lines I saw in my Minecraft logs: [11:54:21 INFO]: Finished downloading /home/noel/.minecraft/libraries/tv/twitch/twitch/5.16/twitch-5.16.jar for job 'Version & Libraries': Local file matches local checksum, using that I think that Minecraft just uses the local files if they match their local checksum. That and the ID thing mentioned in step 5.

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