Minecraft Forums

So this isn't to do with an particular mod it's the maps I'm having problems with. My boyfriend and I have a shared world we send back and forth between the two of us and when he sent it back last week I got this message:

The world Sparklypants contains pre-updated modding data
There may be problems updating it to this version
FML will save a zip to Sparklypants.zip
Do you wish to continue loading?

If I say no obviously no load.
If I say yes it loads the world but not completely unless I walked around it. Items like signs and doors tend not to load. And I'm not sure what else is missing as I haven't completely explored it yet.

I thought maybe my boyfriend had updated his minecraft or was using a mod I didn't have so I asked him. We're both running Minecraft 1.7.2-Forge10.12.0.1024.

Mods used:
TooManyItems
Xray
Teleportation Mod

A few days after the first incident a friend sent me his map which also returned the same message and problems. To see if it was all maps or just those few I downloaded a bunch of adventure maps and it does the same with those. Before you ask yes I'm making sure the maps are 1.7.2 compatable. Does anyone else have the same problem or know how to fix it?

Thanks in advance.

I actually have the exact same problem. I was running 1.6.2 for a long time with a few mods, when I tried updating to 1.7.2 I found the same message as follows:

The world "[WorldName]" contains pre-update modding data
There may be problems updating it to this version
FML will save a zip to "[WorldName]-bunchofnumbers.zip"
Do you wish to continue loading?

This is not unique when I update from 1.6.2 to 1.7.2, I also get the same message when I try 1.6.4 to 1.7.2. Now what's really interesting is that not all of the blocks are actually gone. When I load the world again, now reverted to 1.6.2, the blocks reappear. This indicates to me that the block and item values/IDs are still registered with 1.7.2, but the 1.7 world and code doesn't know how to handle them. In BiblioCraft the Typesetting Table and Printing Press actually still exist and render in the world. The mods themselves are fully functional in 1.7.2.

I have tested this on BiblioCraft and Twilight Forest as well as my own mod to the same effect. I have also tried different forge versions to the same effect.
804 (1.6.2) -> 1024 (1.7.2)
804 (1.6.2) -> 965 (1.6.4) -> 1024 (1.7.2)
965 (1.6.4) -> 1060 (1.7.2)

If anyone knows how this issue might be fixed, I would love to hear your response and I'm sure MusicMonkey would too.

I'm also having a similar issue. were you able to find a resolution?

1.7 is a bit wierd in how it does not use block IDs right now. I don't know of any resolution besides just spawning in the blocks you lost between updates with NEI.