How to Fix a SevTech: Ages of the Sky Server That Keeps Crashing
SevTech: Ages of the Sky shares base SevTech's progression and mod list but needs one specific world-generation setting to actually boot as a skyblock — miss it and the crashes that follow look nothing like a config problem.
See the SevTech Ages of the Sky pack page for sizing before you chase anything else.
1. The missing Sky Block generator setting
This is the sky variant's single most important config, and it's easy to miss because nothing in the install process forces you to set it: server.properties needs generator-settings set to the pack's Sky Block topography preset (documented as {"Topography-Preset":"Sky Block"}) before the world generates for the first time.
Without it, the server generates a normal world instead of the intended sky islands — which then produces world-gen and structure-placement errors that look like a mod bug but are actually just the wrong world type for this pack's content.
2. FoamFix crashes
FoamFix (and FoamFixAPI) are memory-optimization mods some SevTech installs carry, and specific builds are a known server crash cause in this pack. The community FoamFixAPI-Lawful fork is the reported-safe alternative if the memory savings matter.
3. A fixed startup crash from Tombstone: Revived
A specific startup crash traced to the Tombstone: Revived mod was fixed in pack version 3.1.5. If you're on an older release and seeing a crash right at startup, updating is the direct fix rather than removing the mod.
4. Correct Forge build for the pack version
As with every SevTech variant, run the exact Forge build the pack's launcher profile specifies — a close-but-not-exact version is a common, hard-to-spot cause of crashes that have nothing to do with the actual content mods.
FAQ
My SevTech: Ages of the Sky world generates as a normal world, not a sky island — why?+
The sky variant requires its own generator setting in server.properties. If that line is missing or wrong, the server falls back to normal world generation, which this pack's progression and structures aren't built for — producing world-gen errors that look like a mod conflict but are actually a config problem.
What exactly does server.properties need for this pack?+
The generator-settings value needs to be set to the pack's Sky Block topography preset (the documented value is {"Topography-Preset":"Sky Block"}) before the world is first generated — it can't be fixed after the fact without regenerating the world.
Is FoamFix safe to run on a SevTech: Ages of the Sky server?+
The base FoamFix/FoamFixAPI build has caused reported server crashes in SevTech; the community-maintained FoamFixAPI-Lawful fork is the safer choice if you want the memory-saving benefits without the crash risk.
Host SevTech: Ages of the Sky on hardware sized for it
CoalHost takes a backup before any config or world-gen change, so fixing a generator setting never risks the progress you're trying to save.
View SevTech Ages Hosting →