diff --git a/packages/oneclient_core/src/clusters/manager.rs b/packages/oneclient_core/src/clusters/manager.rs
index 72d11bac..9d7a9960 100644
--- a/packages/oneclient_core/src/clusters/manager.rs
+++ b/packages/oneclient_core/src/clusters/manager.rs
@@ -48,6 +48,37 @@ impl ClusterManager {
 	pub async fn create(
 		state: &LauncherState,
 		options: CreateClusterOptions,
+	) -> LauncherResult<Cluster> {
+		let _guard = state.provisioning.lock().await;
+		Self::create_core(state, options).await
+	}
+
+	/// Create a cluster for a version/loader that doesn't exist yet, and provision it.
+	#[tracing::instrument(level = "debug", skip(state))]
+	pub async fn create_provisioned(
+		state: &LauncherState,
+		options: CreateClusterOptions,
+	) -> LauncherResult<Option<Cluster>> {
+		let _guard = state.provisioning.lock().await;
+		if cluster_dao::find_by_version_loader(
+			&state.services.db,
+			&options.mc_version,
+			options.mc_loader as i64,
+		)
+		.await?
+		.is_some()
+		{
+			return Ok(None);
+		}
+		Self::create_core(state, options).await.map(Some)
+	}
+
+	/// Folder-resolve + insert core shared by `create` and `create_provisioned`.
+	/// Callers MUST hold `state.provisioning` — this does not lock.
+	#[tracing::instrument(level = "debug", skip(state))]
+	async fn create_core(
+		state: &LauncherState,
+		options: CreateClusterOptions,
 	) -> LauncherResult<Cluster> {
 		let name = Self::sanitize_name(&options.name);
 		if name.is_empty() {
diff --git a/packages/oneclient_core/src/clusters/provision.rs b/packages/oneclient_core/src/clusters/provision.rs
index 898a3657..18cc8daf 100644
--- a/packages/oneclient_core/src/clusters/provision.rs
+++ b/packages/oneclient_core/src/clusters/provision.rs
@@ -39,13 +39,13 @@ pub async fn ensure_from_bundles(state: &LauncherState) -> LauncherResult<Vec<Cl
 
         let mc_version = group.mc_version.clone();
         let name = format!("{mc_version} {loader}");
-        match ClusterManager::create(
+        match ClusterManager::create_provisioned(
             state,
             CreateClusterOptions::new(name, mc_version.clone(), loader),
         )
         .await
         {
-            Ok(cluster) => {
+            Ok(Some(cluster)) => {
                 tracing::info!(
                     cluster_id = cluster.id,
                     mc_version = %cluster.mc_version,
@@ -54,6 +54,7 @@ pub async fn ensure_from_bundles(state: &LauncherState) -> LauncherResult<Vec<Cl
                 );
                 created.push(cluster);
             }
+            Ok(None) => {}
             Err(err) => {
                 tracing::warn!(
                     mc_version = %mc_version,
@@ -100,13 +101,13 @@ pub async fn ensure_from_versions(state: &LauncherState) -> LauncherResult<Vec<C
         }
 
         let name = format!("{mc_version} {loader}");
-        match ClusterManager::create(
+        match ClusterManager::create_provisioned(
             state,
             CreateClusterOptions::new(name, mc_version.clone(), loader),
         )
         .await
         {
-            Ok(cluster) => {
+            Ok(Some(cluster)) => {
                 tracing::info!(
                     cluster_id = cluster.id,
                     mc_version = %cluster.mc_version,
@@ -115,6 +116,7 @@ pub async fn ensure_from_versions(state: &LauncherState) -> LauncherResult<Vec<C
                 );
                 created.push(cluster);
             }
+            Ok(None) => {}
             Err(err) => {
                 tracing::warn!(
                     mc_version = %mc_version,
diff --git a/packages/oneclient_core/src/dev.rs b/packages/oneclient_core/src/dev.rs
index 7a00c356..4ea18906 100644
--- a/packages/oneclient_core/src/dev.rs
+++ b/packages/oneclient_core/src/dev.rs
@@ -242,6 +242,7 @@ pub async fn ephemeral_state() -> LauncherResult<Arc<LauncherState>> {
 		images: crate::images::ImageCacheStore::new(),
 		games: crate::game::GameProcessManager::new(),
 		discord: crate::discord::DiscordRpc::spawn(false),
+		provisioning: tokio::sync::Mutex::new(()),
 	}))
 }
 
diff --git a/packages/oneclient_core/src/recovery.rs b/packages/oneclient_core/src/recovery.rs
index abdedb0b..16e42b07 100644
--- a/packages/oneclient_core/src/recovery.rs
+++ b/packages/oneclient_core/src/recovery.rs
@@ -40,6 +40,11 @@ impl RecoveryReport {
 pub async fn reconstruct_from_disk(state: &LauncherState) -> LauncherResult<RecoveryReport> {
 	let mut report = RecoveryReport::default();
 
+	// Hold the provisioning lock across the whole scan+adopt so a concurrent
+	// cluster create (folder-on-disk written before its DB row commits) can't be
+	// misclassified as an orphan and adopted into a duplicate row.
+	let _guard = state.provisioning.lock().await;
+
 	let clusters_dir = paths::clusters_dir()?;
 	let orphans = orphan_cluster_folders(&state.services.db, &clusters_dir).await?;
 	if orphans.is_empty() {
diff --git a/packages/oneclient_core/src/state.rs b/packages/oneclient_core/src/state.rs
index 2f829022..2e5ed101 100644
--- a/packages/oneclient_core/src/state.rs
+++ b/packages/oneclient_core/src/state.rs
@@ -40,6 +40,7 @@ pub struct LauncherState {
 	pub images: ImageCacheStore,
 	pub games: crate::game::GameProcessManager,
 	pub discord: DiscordRpc,
+	pub provisioning: Mutex<()>,
 }
 
 impl LauncherState {
@@ -75,6 +76,7 @@ impl LauncherState {
 			images: ImageCacheStore::new(),
 			games: crate::game::GameProcessManager::new(),
 			discord,
+			provisioning: Mutex::new(()),
 		});
 
 		STATE