Converting vanilla server to FTB Lite 3

[Spheres]

Hello there,

I've been running a 1.15.2 vanilla server for a couple of people for a few weeks and was wondering if I could convert it to FTB Lite 3.

I set up the Lite 3 server and plugged the vanilla world folder into it. When I run the server I got a lot of "Couldn't load chunk" (the log is attached). When I logged on, it was the correct world with the correct spawn point, but every trace of previous play was absent, a.k.a. it generated a new world from the correct seed.
Also, still water was left untouched but waterfalls were now lava.

Any thoughts/ideas on whether or not such a migration is possible and if so, how? Needing to generate new chunks to access modded ores does not pose a problem as the server mostly holds semi-survival/semi-creative builds, I just wish to transport the buildings to Lite, items can be missed and replaced.

Thanks in advance,
Spheres

 

[lenscas]

first thing first: using a world that had vanilla play for modded isn't really recommended as some resources will only be able to be found in terrain generated after the conversion. Also, other problems may or may not happen depending on the mods.

Second thing: you where playing on 1.15.2. FTB lite is 1.7.10. Going from minecraft 1.15.2 to 1.7.10 will already cause problems and may very well be impossible. In fact, it would surprise me more if it CAN be done then if it can NOT be done.