unknown snapshot: N — the id does not exist. Check list; ids are
never reused.
blob missing from CAS: <hex> — store corruption (or a store copied
incompletely). Rollback aborts rather than writing a partial world;
--on-missing-blob skip-chunk (rollback/export) continues without the
affected chunks. Restore the store from the secondary copy, then
investigate.
cannot derive region path for dim ... (UnknownRegionPath) — a
custom-dimension region whose folder is unknown, or
--on-missing-file error refusing to guess. Run it against a world
tree with the same folder layout the backup came from so sibling
derivation can work, or accept that the region cannot be placed.
unsupported schema version — the store was written by a newer (or
older) binary. The project is pre-release: recreate the store, don’t
migrate.
Region parse failures name the file (failed to process region file ...). Torn tails from interrupted saves are tolerated when
unreferenced; genuinely corrupt sector runs fail loudly by design.
Slow commands: rerun with --timing (release build) and compare
phases; for backup-path slowdowns prefer --timing --json, which
carries the per-region breakdown.