diff --git a/foundations/core/packages/model/src/migration.ts b/foundations/core/packages/model/src/migration.ts
index c82b8c2eaf5..9c19a97a60b 100644
--- a/foundations/core/packages/model/src/migration.ts
+++ b/foundations/core/packages/model/src/migration.ts
@@ -108,6 +108,8 @@ export interface MigrationClient {
   create: <T extends Doc>(domain: Domain, doc: T | T[]) => Promise<void>
   delete: <T extends Doc>(domain: Domain, _id: Ref<T>) => Promise<void>
   deleteMany: <T extends Doc>(domain: Domain, query: DocumentQuery<T>) => Promise<void>
+  // Check the physical storage domain, including legacy domains no longer present in the active model.
+  domainExists: (domain: Domain) => Promise<boolean>
 
   hierarchy: Hierarchy
   model: ModelDb
diff --git a/foundations/server/packages/postgres/src/utils.ts b/foundations/server/packages/postgres/src/utils.ts
index 469904e3a93..3c0df2258a9 100644
--- a/foundations/server/packages/postgres/src/utils.ts
+++ b/foundations/server/packages/postgres/src/utils.ts
@@ -325,12 +325,39 @@ export class DBCollectionHelper implements DomainHelperOperations {
   async create (domain: Domain): Promise<void> {}
 
   async exists (domain: Domain): Promise<boolean> {
-    // Always exists. We don't need to check for index existence
-    return true
+    // Migrations can reference legacy domains that were removed from the current model,
+    // so this must check the physical table instead of the initialized model-domain set.
+    const tableName = translateDomain(domain)
+    const res = await this.client.execute(
+      `
+        SELECT 1
+        FROM information_schema.tables
+        WHERE table_schema = 'public'
+          AND table_name = $1
+        LIMIT 1
+      `,
+      [tableName]
+    )
+    return res.length > 0
   }
 
   async listDomains (): Promise<Set<Domain>> {
-    return this.domains
+    const rows = await this.client.execute(`
+      SELECT table_name
+      FROM information_schema.tables
+      WHERE table_schema = 'public'
+        AND table_name NOT LIKE 'pg_%'
+        AND table_name NOT LIKE 'cluster_%'
+        AND table_name NOT LIKE 'kv_%'
+        AND table_name NOT LIKE 'node_%'
+    `)
+    const tableNames = new Set(rows.map((it) => it.table_name as Domain))
+    for (const domain of this.domains) {
+      if (tableNames.has(translateDomain(domain) as Domain)) {
+        tableNames.add(domain)
+      }
+    }
+    return tableNames
   }
 
   async createIndex (domain: Domain, value: string | FieldIndexConfig<Doc>, options?: { name: string }): Promise<void> {}
diff --git a/models/chunter/src/migration.ts b/models/chunter/src/migration.ts
index abfa2b41395..87ed38f030c 100644
--- a/models/chunter/src/migration.ts
+++ b/models/chunter/src/migration.ts
@@ -156,16 +156,20 @@ export async function createRandom (client: MigrationUpgradeClient, tx: TxOperat
 }
 
 async function convertCommentsToChatMessages (client: MigrationClient): Promise<void> {
-  await client.update(
-    DOMAIN_COMMENT,
-    { _class: 'chunter:class:Comment' as Ref<Class<Doc>> },
-    { _class: chunter.class.ChatMessage }
-  )
-  await client.move(DOMAIN_COMMENT, { _class: chunter.class.ChatMessage }, DOMAIN_ACTIVITY)
+  if (await client.domainExists(DOMAIN_COMMENT)) {
+    await client.update(
+      DOMAIN_COMMENT,
+      { _class: 'chunter:class:Comment' as Ref<Class<Doc>> },
+      { _class: chunter.class.ChatMessage }
+    )
+    await client.move(DOMAIN_COMMENT, { _class: chunter.class.ChatMessage }, DOMAIN_ACTIVITY)
+  }
 }
 
 async function removeBacklinks (client: MigrationClient): Promise<void> {
-  await client.deleteMany(DOMAIN_COMMENT, { _class: 'chunter:class:Backlink' as Ref<Class<Doc>> })
+  if (await client.domainExists(DOMAIN_COMMENT)) {
+    await client.deleteMany(DOMAIN_COMMENT, { _class: 'chunter:class:Backlink' as Ref<Class<Doc>> })
+  }
   await client.deleteMany(DOMAIN_ACTIVITY, {
     _class: activity.class.DocUpdateMessage,
     objectClass: 'chunter:class:Backlink' as Ref<Class<Doc>>
diff --git a/server/tool/src/upgrade.ts b/server/tool/src/upgrade.ts
index 4792ef47cb0..21a8942e820 100644
--- a/server/tool/src/upgrade.ts
+++ b/server/tool/src/upgrade.ts
@@ -127,6 +127,12 @@ export class MigrateClientImpl implements MigrationClient {
     await this.lowLevel.rawDeleteMany(domain, query)
   }
 
+  async domainExists (domain: Domain): Promise<boolean> {
+    const adapter = this.pipeline.context.adapterManager?.getAdapter(domain, false)
+    const helper = adapter?.helper?.()
+    return helper !== undefined ? await helper.exists(domain) : true
+  }
+
   async fullReindex (): Promise<void> {
     await this.queue.send(this.ctx, this.wsIds.uuid, [workspaceEvents.fullReindex()])
   }