H3 and H4 are done for me, since Halo 3 was so restrictive, and most of my Halo 4 career was matchmaking. Reach, however...I'm still combing through those, and it's not too convenient since you have to load all the saved items EVERY time you play a game. (POST EDIT: Oh, AND it doesn't load until you actually ask it to load manually.) However, I'm sorta-lucky since (nearly) all of the custom maps are in Forge World, so at least I don't have to load a different map each time. So far my only worry is uploading a gametype and missing a map that goes with it, but I'm making progress, I guess.

You guys?

First I've herd of this. Don't really follow much "343" stuff.

Nobody does. Halo is dead.

Is this for 360...or what?

It's for MCC. 343 will scour your Fileshare from the 360 days, and bring over whatever stuff you have in Halo 3/Reach over to your Xbone/Windows account. It's a one-time deal, likely never to be repeated, so if you want any map/gametype copied over, these two days are your only opportunity.

Get which done, now? I've got a few choice maps and gametypes from 3 and from Reach. But if they're already in my fileshares for those games, they're going to get sucked up in that mass import already, right?

Correct, they will take anything in your fileshare that is a GAMETYPE on August 12. Then giving people time to change all the items in their fileshare to Maps (or if you only have a few as you seem they will already be in there) on August 26. They are doing it this way a) for background technicaly reasons and b) so you can fill up your fileshare with 1 type allowing you to upload 2x the amount.

Any that aren’t, need to be.

I've been real lucky with Halo 3, I only have about 15 gametypes. Halo 4 is good, but there are so many modded content on there, I don't know what'll take and what won't.

Reach...is another story.

Just a friendly reminder that 343 is doing a transfer of your entire fileshare so it can be brought into MCC. However, they will do 1 day, August 12 for gametypes on (so fill them up NOW), and then August 26 for Maps. Just a friendly PSA to get that done ASAP for Gametypes.

Bluerunner, we need invasion maps! Everyone else who has maps, please do it, even if you don't have MCC, so everyone can enjoy your creations!

Further note, this is Halo 3, halo reach and Halo 4.

Get which done, now? I've got a few choice maps and gametypes from 3 and from Reach. But if they're already in my fileshares for those games, they're going to get sucked up in that mass import already, right?

Bluerunner, we need invasion maps! Everyone else who has maps, please do it, even if you don't have MCC, so everyone can enjoy your creations!

Further note, this is Halo 3, halo reach and Halo 4.