Take the 2-minute tour ×
Arqade is a question and answer site for passionate videogamers on all platforms. It's 100% free, no registration required.

In Minecraft, nearly every tutorial on how to install a MOD tells you to remove the META-INF folder. However none of the ones I found tell you what it is. I don't like the idea of deleting a folder without knowing what it is or what it does.

So what is the META-INF folder, and why should I delete it?

share|improve this question

1 Answer 1

up vote 48 down vote accepted

Because Minecraft is digitally signed. META-INF contains the manifest, but also a signature file (MOJANG_C.SF) that accounts for all the files within the JAR and their checksums, and Mojang's actual signature (MOJANG_C.DSA).

When that signature checks out, you know it wasn't tampered with and comes from a trusted source (in this case, Mojang). When you do tamper with it (by installing mods), the signature is invalid and Minecraft won't start at all.

By deleting the META-INF directory, you remove the signature completely. Depending on your security settings, you might get an "unknown publisher" warning, but you'll be able to run it.

More detailed info: JAR File Specification

share|improve this answer
2  
Ah, one of those other properties, the big one. –  Jeff Mercado Jul 31 '11 at 18:51

protected by Community Apr 28 '12 at 21:28

Thank you for your interest in this question. Because it has attracted low-quality answers, posting an answer now requires 10 reputation on this site.

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.