diff --git a/backend/cmd/backend/main.go b/backend/cmd/backend/main.go
index d6ecdc0..be1b997 100644
--- a/backend/cmd/backend/main.go
+++ b/backend/cmd/backend/main.go
@@ -266,6 +266,21 @@ func run(ctx context.Context) (err error) {
 	)
 	runtimeGateway.svc = runtimeSvc
 
+	// Run a single reconciliation pass before the dev-sandbox
+	// bootstrap so any runtime row pointing at a vanished engine
+	// container (host reboot wiped /tmp/galaxy-game-state/<uuid>;
+	// `tools/local-dev`'s `prune-broken-engines` target reaped the
+	// husk) is already cascaded through `markRemoved` → lobby
+	// `cancelled` by the time the bootstrap walks the sandbox list.
+	// Without this pre-tick the bootstrap would reuse the
+	// soon-to-be-cancelled game and force the developer into a
+	// second `make up` cycle to land a healthy sandbox. Failures are
+	// non-fatal: the periodic ticker started later catches up, and
+	// the worst case degrades to the legacy two-cycle recovery.
+	if err := runtimeSvc.Reconciler().Tick(ctx); err != nil {
+		logger.Warn("pre-bootstrap reconciler tick failed", zap.Error(err))
+	}
+
 	if err := devsandbox.Bootstrap(ctx, devsandbox.Deps{
 		Users:          userSvc,
 		Lobby:          lobbySvc,
diff --git a/tools/local-dev/Makefile b/tools/local-dev/Makefile
index a36cbbb..c0efd73 100644
--- a/tools/local-dev/Makefile
+++ b/tools/local-dev/Makefile
@@ -1,4 +1,4 @@
-.PHONY: help up down logs status rebuild clean psql logs-backend logs-gateway logs-mail build-engine stop-engines wait
+.PHONY: help up down logs status rebuild clean psql logs-backend logs-gateway logs-mail build-engine stop-engines prune-broken-engines wait
 
 .DEFAULT_GOAL := help
 
@@ -17,6 +17,7 @@ help:
 	@echo "  make rebuild        Force rebuild of backend / gateway images and bring up"
 	@echo "  make build-engine   Build the engine image $(ENGINE_IMAGE) used by the dev sandbox"
 	@echo "  make stop-engines   Stop and remove only the per-game engine containers"
+	@echo "  make prune-broken-engines  Remove non-running engine containers Docker can't heal (run inside 'up')"
 	@echo "  make clean          Stop everything (incl. engines) and wipe volumes + game state"
 	@echo "  make logs           Tail all logs"
 	@echo "  make logs-backend   Tail only the backend logs"
@@ -32,7 +33,7 @@ help:
 	@echo "Default login for the auto-provisioned dev sandbox: dev@local.test"
 	@echo "(see BACKEND_DEV_SANDBOX_EMAIL in .env). Login code: 123456."
 
-up: build-engine
+up: build-engine prune-broken-engines
 	$(COMPOSE) up -d --wait
 
 rebuild: build-engine
@@ -70,6 +71,34 @@ stop-engines:
 		docker rm -f $$ids >/dev/null; \
 	fi
 
+# Remove engine containers Docker can no longer heal on its own.
+# After a host reboot, the per-game bind-mount source under
+# /tmp/galaxy-game-state/<uuid> may have been wiped (macOS clears
+# /private/tmp on reboot), so `restart: unless-stopped` cannot
+# revive the container — Docker refuses to start it with a missing
+# bind-mount source and leaves it stuck in `exited` / `created`
+# state. This target prunes the husks before `compose up`; the
+# backend's pre-bootstrap reconciler tick (`backend/cmd/backend/main.go`)
+# then cascades the orphan runtime row to `removed`, the lobby
+# cancels the game, and the dev-sandbox bootstrap purges the
+# cancelled tile and provisions a fresh sandbox in the same
+# `make up` cycle. Healthy `running` / `restarting` containers are
+# left intact so a long-lived sandbox survives normal up/down
+# cycles.
+prune-broken-engines:
+	@ids=""; \
+	for cid in $$(docker ps -aq --filter label=$(ENGINE_LABEL) 2>/dev/null); do \
+		state=$$(docker inspect -f '{{.State.Status}}' $$cid 2>/dev/null); \
+		case "$$state" in \
+			running|restarting) ;; \
+			*) ids="$$ids $$cid";; \
+		esac; \
+	done; \
+	if [ -n "$$ids" ]; then \
+		echo "removing non-running engine containers (post-reboot cleanup):$$ids"; \
+		docker rm -f $$ids >/dev/null; \
+	fi
+
 logs:
 	$(COMPOSE) logs -f --tail=100
 
diff --git a/tools/local-dev/README.md b/tools/local-dev/README.md
index 8597fb5..f21ec2e 100644
--- a/tools/local-dev/README.md
+++ b/tools/local-dev/README.md
@@ -226,6 +226,19 @@ make status         docker compose ps
   engine containers via the `org.opencontainers.image.title=
   galaxy-game-engine` label. To stop them by hand without touching
   the rest of the stack, `make stop-engines`.
+- **Engine container exits with `bind source path does not exist:
+  /tmp/galaxy-game-state/<uuid>` after a host reboot** — macOS clears
+  `/private/tmp` on reboot, so the per-game state directory the
+  long-lived engine container bind-mounts is gone and Docker refuses
+  to restart it under `restart: unless-stopped`. `make up` auto-heals
+  this in one cycle: `prune-broken-engines` (runs as part of `up`)
+  removes every engine container that is not in `running` /
+  `restarting` state, the backend's pre-bootstrap reconciler tick
+  cascades the orphan runtime row to `removed`, the lobby cancels
+  the matching sandbox game, and the dev-sandbox bootstrap purges
+  the cancelled tile and provisions a fresh sandbox with a brand
+  new state directory. To run the cleanup by hand without restarting
+  the rest of the stack, `make prune-broken-engines`.
 - **`make up` reports a build error mentioning `pkg/cronutil`** —
   upstream module list drifted; copy any new `pkg/<name>/` line into
   the local-dev `backend.Dockerfile` / `gateway.Dockerfile` to match