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.
- 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
- 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".
- 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.
- Open the JSON file. You should see "id": "something". Rename the something inside the original quotation marks with what you renamed the folder to.
- 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.