Anuken/Mindustry · error · IOException

Invalid schematic: Too many blocks.

Error message

Invalid schematic: Too many blocks.

What it means

Thrown by Schematics.read when limitSchematicSize is enabled and the total block count read from the stream exceeds 128*128 (16384). This is the area-based cap complementing the dimension cap: even a small footprint schematic could in theory pack many blocks, so the total is bounded by the maximum grid area.

Source

Thrown at core/src/mindustry/game/Schematics.java:625

            String[] labels = null;

            //try to read the categories, but skip if it fails
            try{
                labels = JsonIO.read(String[].class, map.get("labels", "[]"));
            }catch(Exception ignored){}

            IntMap<Block> blocks = new IntMap<>();
            int length = stream.readUnsignedByte();
            for(int i = 0; i < length; i++){
                String name = stream.readUTF();
                Block block = Vars.content.getByName(ContentType.block, SaveFileReader.fallback.get(name, name));
                blocks.put(i, block == null || block instanceof LegacyBlock ? Blocks.air : block);
            }

            int total = stream.readInt();

            if(limitSchematicSize && total > 128 * 128) throw new IOException("Invalid schematic: Too many blocks.");

            Reads read = new Reads(stream);

            Seq<Stile> tiles = new Seq<>(total);
            for(int i = 0; i < total; i++){
                Block block = blocks.get(stream.readByte());
                int position = stream.readInt();
                Object config = ver == 0 ? mapConfig(block, stream.readInt(), position) : TypeIO.readObject(read, false, mapper);
                byte rotation = stream.readByte();
                if(block != Blocks.air){
                    tiles.add(new Stile(block, Point2.x(position), Point2.y(position), config, rotation));
                }
            }

            Schematic out = new Schematic(tiles, map, width, height);
            if(labels != null) out.labels.addAll(labels);
            return out;
        }

View on GitHub (pinned to f695ad7e60)

Solutions

1. Reduce the block count (split or simplify the schematic) to <= 16384 tiles.
2. Set Schematics.limitSchematicSize = false if oversized schematics are intentional.
3. Re-export from a valid editor selection that fits the cap.

Example fix

// before
Schematic s = Schematics.read(input); // throws if total > 16384

// after
Schematics.limitSchematicSize = false;
Schematic s = Schematics.read(input);

// if you know block count ahead of time
if(limitSchematicSize && total > 128*128){
    ui.showErrorMessage("Too many blocks (max " + (128*128) + ")");
    return;
}

try{ Schematic s = Schematics.read(input); }catch(IOException e){ ui.showErrorMessage("Schematic has too many blocks"); }

When it happens

Trigger: A schematic whose 'total' field (stream.readInt()) is > 16384 with limitSchematicSize == true. Block count exceeding the 128x128 grid capacity.

Common situations: Densely packed schematics; schematics created by automation that exceed the block budget; combined/merged schematics that overflow.

Related errors

• Invalid schematic: Too large (max possible size is 128x128)
• Not a schematic file (missing header).
• Unknown version: {ver} (are you trying to load a schematic f
• Image is too large (maximum size is {MapResizeDialog.maxSize
• Unknown save version: {}. Are you trying to load a save from

AI-assisted analysis of Anuken/Mindustry@f695ad7e60 (2026-08-14). Data as JSON: /api/errors/b6d744897c907b49. Report an issue: GitHub.