diff --git a/backend/open_webui/migrations/versions/38d63c18f30f_add_oauth_session_table.py b/backend/open_webui/migrations/versions/38d63c18f30f_add_oauth_session_table.py
index 8fd7656633..b212c7f43a 100644
--- a/backend/open_webui/migrations/versions/38d63c18f30f_add_oauth_session_table.py
+++ b/backend/open_webui/migrations/versions/38d63c18f30f_add_oauth_session_table.py
@@ -22,30 +22,6 @@ def upgrade() -> None:
     inspector = sa.inspect(op.get_bind())
     existing_tables = set(inspector.get_table_names())
 
-    # ── Fix user.id PK only when it is genuinely wrong ────────────────
-    # On databases migrated from the old Peewee layer the PK may have
-    # drifted.  Fresh installs (init migration 7e5b5dc7342b) already
-    # have a correct PK on 'id', so we must NOT attempt to re-create it
-    # — PostgreSQL will reject a duplicate PRIMARY KEY constraint.
-    pk_columns = inspector.get_pk_constraint('user')['constrained_columns']
-
-    if pk_columns != ['id']:
-        columns = inspector.get_columns('user')
-        id_column = next((col for col in columns if col['name'] == 'id'), None)
-        unique_constraints = inspector.get_unique_constraints('user')
-        unique_columns = {tuple(u['column_names']) for u in unique_constraints}
-
-        if id_column:
-            with op.batch_alter_table('user') as batch_op:
-                if pk_columns:
-                    batch_op.drop_constraint(
-                        inspector.get_pk_constraint('user')['name'],
-                        type_='primary',
-                    )
-                if ('id',) not in unique_columns:
-                    batch_op.create_unique_constraint('uq_user_id', ['id'])
-                batch_op.create_primary_key('pk_user_id', ['id'])
-
     # ── Create oauth_session table (idempotent) ───────────────────────
     if 'oauth_session' not in existing_tables:
         op.create_table(
diff --git a/backend/open_webui/migrations/versions/3af16a1c9fb6_update_user_table.py b/backend/open_webui/migrations/versions/3af16a1c9fb6_update_user_table.py
index b678b5393b..e3767a71a7 100644
--- a/backend/open_webui/migrations/versions/3af16a1c9fb6_update_user_table.py
+++ b/backend/open_webui/migrations/versions/3af16a1c9fb6_update_user_table.py
@@ -19,10 +19,18 @@ depends_on: Union[str, Sequence[str], None] = None
 
 
 def upgrade() -> None:
-    op.add_column('user', sa.Column('username', sa.String(length=50), nullable=True))
-    op.add_column('user', sa.Column('bio', sa.Text(), nullable=True))
-    op.add_column('user', sa.Column('gender', sa.Text(), nullable=True))
-    op.add_column('user', sa.Column('date_of_birth', sa.Date(), nullable=True))
+    conn = op.get_bind()
+    inspector = sa.inspect(conn)
+    user_cols = {c['name'] for c in inspector.get_columns('user')}
+
+    if 'username' not in user_cols:
+        op.add_column('user', sa.Column('username', sa.String(length=50), nullable=True))
+    if 'bio' not in user_cols:
+        op.add_column('user', sa.Column('bio', sa.Text(), nullable=True))
+    if 'gender' not in user_cols:
+        op.add_column('user', sa.Column('gender', sa.Text(), nullable=True))
+    if 'date_of_birth' not in user_cols:
+        op.add_column('user', sa.Column('date_of_birth', sa.Date(), nullable=True))
 
 
 def downgrade() -> None:
diff --git a/backend/open_webui/migrations/versions/3e0e00844bb0_add_knowledge_file_table.py b/backend/open_webui/migrations/versions/3e0e00844bb0_add_knowledge_file_table.py
index da60344cdd..70c0562749 100644
--- a/backend/open_webui/migrations/versions/3e0e00844bb0_add_knowledge_file_table.py
+++ b/backend/open_webui/migrations/versions/3e0e00844bb0_add_knowledge_file_table.py
@@ -24,6 +24,13 @@ depends_on: Union[str, Sequence[str], None] = None
 
 
 def upgrade() -> None:
+    conn = op.get_bind()
+    inspector = sa.inspect(conn)
+    existing_tables = set(inspector.get_table_names())
+
+    if 'knowledge_file' in existing_tables:
+        return  # Already created — skip everything
+
     op.create_table(
         'knowledge_file',
         sa.Column('id', sa.Text(), primary_key=True),