You need to make sure you run your 1.6 world using the LATEST 1.6.4 version of Forge AND THEN update to 1.7.10.

This will work fine IF the mods are prepared for the update.

If not shit like this happens and you have to start new.

It's up to the mods to fix update issues like this by having a '1.7 prep' version you can run that will save the proper information to the world.

I am running forge 9.11.1.965 on 1.6.4. Pretty much all the mods are updated to the latest 1.6.4 version and I'm barely getting any "This item will  NOT survive a 1.7 upgrade". The thing is, i don't have some mods on 1.7 instance that i have on 1.6.4 (such as gregtech, ars magica, minechem, and dartcraft). Should I remove them on 1.6.4, run a 1.6.4 instance without them and then try updating? Maybe that's causing it?

 

I'm sure it's not bibliocraft. I removed it on 1.7 and the fancy lamps get replaced with steam. All the mod stuff is fine, even TC pickaxes and focus pouches in my inventory.

 

my 1.6.4 log (If you need it)

https://gist.github.com/anonymous/c0ae0971a5213a6ed817

Never mind, was an ID conflict You can close now..

Anyway, thank you!