don't generate option for more 2>3 or 3>8 or worse 4>4 balancers

not sure if I'm missing something but the mod is very intuitive and i would love for it to work instead of me opening up my bp folder and look for the exact bp balancer

more balancers wont gen i just listed a few

i get the error belt family unavailable or blueprint conversion failed

Can you provide a modlist? I also would like to know your Factorio version and your factorio-current.log
It sounds like it failed to create a preview for some reason.

Can you provide a modlist? I also would like to know your Factorio version and your factorio-current.log
It sounds like it failed to create a preview for some reason.

I have the same issue. Here's my modlist, running 2.0.77.

  "name": "base",
  "name": "elevated-rails",
  "name": "quality",
  "name": "space-age",
  "name": "aai-loaders",
  "name": "aai-loaders-lane-filter",
  "name": "aai-vehicles-miner",
  "name": "belt-balancer-planner",
  "name": "blueprint-sandboxes",
  "name": "bobinserters",
  "name": "combat-mechanics-overhaul",
  "name": "easy-roboport-placement-updated",
  "name": "even-distribution",
  "name": "factory-planning-room",
  "name": "flib",
  "name": "HeroTurretRedux",
  "name": "HugeElectricPole",
  "name": "infinite_worker_robot_capacity_research",
  "name": "inventory-repair",
  "name": "mining-patch-planner",
  "name": "Orphan Finder",
  "name": "Productivity",
  "name": "Progressive_Running_2_0",
  "name": "QualityEffectsFixed",
  "name": "quick-swap",
  "name": "RailSignalPlanner",
  "name": "RateCalculator",
  "name": "Repair_Turret",
  "name": "RPGsystem",
  "name": "silent-belts-5",
  "name": "squeak-through-2",
  "name": "StatsGui",
  "name": "tank-upgrade-brake",
  "name": "Todo-List",
  "name": "too-many-prods",
  "name": "Trashcan",
  "name": "tree-healing",
  "name": "VehicleSnap",
  "name": "visible-planets",
  "name": "WideChests",
  "name": "WideChestsAllTypes",
  "name": "WideChestsLogistic",
  "name": "WideChestsUnlimited",
  "name": "wood-stack-to-1k",
  "name": "Wood-Walls",
  "name": "WorkerRobotsBatteryResearch",

The problem persists even when all mods shown in the context menu for the belts are disabled (AAI loaders/lane filtering, silent belts, combat mechanics overhaul).

Here's my factorio-current.log:
https://pastebin.com/yiF9JFH4

Seems like an api change caused some problems
Factorio 2.0 it is calleed neighbours but in 2.1 its called underground_belt_neighbour

That fixed the issue, thanks :)