diff --git a/astrbot/core/db/vec_db/faiss_impl/document_storage.py b/astrbot/core/db/vec_db/faiss_impl/document_storage.py
index 116c43be1..d0310d750 100644
--- a/astrbot/core/db/vec_db/faiss_impl/document_storage.py
+++ b/astrbot/core/db/vec_db/faiss_impl/document_storage.py
@@ -96,36 +96,29 @@ class DocumentStorage:
 
     async def _initialize_fts5(self, executor) -> None:
         try:
-            try:
-                await executor.execute(
-                    text(
-                        f"""
-                        CREATE VIRTUAL TABLE IF NOT EXISTS {FTS_TABLE_NAME}
-                        USING fts5(
-                            search_text,
-                            content='',
-                            contentless_delete=1,
-                            tokenize='unicode61'
-                        )
-                        """,
-                    ),
+            await self._create_fts5_table(executor, if_not_exists=True)
+
+            is_valid_fts5, has_contentless_delete = await self._inspect_fts5_table(
+                executor,
+            )
+            if not is_valid_fts5:
+                logger.warning(
+                    f"Detected incompatible legacy table `{FTS_TABLE_NAME}` in "
+                    f"{self.db_path}; recreating FTS5 table.",
                 )
-                self._fts_contentless_delete = True
-            except Exception:
-                await executor.execute(
-                    text(
-                        f"""
-                        CREATE VIRTUAL TABLE IF NOT EXISTS {FTS_TABLE_NAME}
-                        USING fts5(
-                            search_text,
-                            content='',
-                            tokenize='unicode61'
-                        )
-                        """,
-                    ),
+                await executor.execute(text(f"DROP TABLE IF EXISTS {FTS_TABLE_NAME}"))
+                await self._create_fts5_table(executor, if_not_exists=False)
+
+                is_valid_fts5, has_contentless_delete = await self._inspect_fts5_table(
+                    executor,
                 )
-                self._fts_contentless_delete = False
+                if not is_valid_fts5:
+                    raise RuntimeError(
+                        f"Failed to create a valid FTS5 table `{FTS_TABLE_NAME}`",
+                    )
+
             self.fts5_available = True
+            self._fts_contentless_delete = has_contentless_delete
         except Exception as e:
             self.fts5_available = False
             self._fts_contentless_delete = False
@@ -134,6 +127,69 @@ class DocumentStorage:
                 f"falling back to in-memory BM25 sparse retrieval: {e}",
             )
 
+    async def _create_fts5_table(self, executor, if_not_exists: bool) -> None:
+        create_clause = (
+            "CREATE VIRTUAL TABLE IF NOT EXISTS"
+            if if_not_exists
+            else "CREATE VIRTUAL TABLE"
+        )
+        try:
+            await executor.execute(
+                text(
+                    f"""
+                    {create_clause} {FTS_TABLE_NAME}
+                    USING fts5(
+                        search_text,
+                        content='',
+                        contentless_delete=1,
+                        tokenize='unicode61'
+                    )
+                    """,
+                ),
+            )
+        except Exception:
+            await executor.execute(
+                text(
+                    f"""
+                    {create_clause} {FTS_TABLE_NAME}
+                    USING fts5(
+                        search_text,
+                        content='',
+                        tokenize='unicode61'
+                    )
+                    """,
+                ),
+            )
+
+    async def _inspect_fts5_table(self, executor) -> tuple[bool, bool]:
+        schema_result = await executor.execute(
+            text(
+                """
+                SELECT sql
+                FROM sqlite_master
+                WHERE type='table' AND name=:table_name
+                """,
+            ),
+            {"table_name": FTS_TABLE_NAME},
+        )
+        create_sql = schema_result.scalar_one_or_none()
+        if not create_sql:
+            return False, False
+
+        normalized_sql = create_sql.lower()
+        if "virtual table" not in normalized_sql or "using fts5" not in normalized_sql:
+            return False, False
+
+        pragma_result = await executor.execute(
+            text(f"PRAGMA table_info({FTS_TABLE_NAME})"),
+        )
+        columns = {row[1] for row in pragma_result.fetchall()}
+        if "search_text" not in columns:
+            return False, False
+
+        normalized_sql_no_whitespace = "".join(normalized_sql.split())
+        return True, "contentless_delete=1" in normalized_sql_no_whitespace
+
     async def connect(self) -> None:
         """Connect to the SQLite database."""
         if self.engine is None:
diff --git a/tests/unit/test_document_storage_fts.py b/tests/unit/test_document_storage_fts.py
index 753c371ef..a7dd32c94 100644
--- a/tests/unit/test_document_storage_fts.py
+++ b/tests/unit/test_document_storage_fts.py
@@ -1,3 +1,5 @@
+import sqlite3
+
 import pytest
 
 from astrbot.core.db.vec_db.faiss_impl.document_storage import DocumentStorage
@@ -73,3 +75,29 @@ async def test_document_storage_fts_delete_skips_missing_fts_row(tmp_path):
     assert await storage.get_document_by_doc_id("legacy-chunk") is None
 
     await storage.close()
+
+
+@pytest.mark.asyncio
+async def test_document_storage_fts_recovers_from_legacy_non_fts_table(tmp_path):
+    db_path = tmp_path / "doc.db"
+    conn = sqlite3.connect(db_path)
+    conn.execute("CREATE TABLE documents_fts (rowid INTEGER PRIMARY KEY)")
+    conn.commit()
+    conn.close()
+
+    storage = DocumentStorage(str(db_path))
+    await storage.initialize()
+
+    assert storage.fts5_available is True
+
+    await storage.insert_document(
+        doc_id="legacy-fix",
+        text="legacy fts recovery text",
+        metadata={"kb_doc_id": "doc-1", "kb_id": "kb-1", "chunk_index": 0},
+    )
+    results = await storage.search_sparse(["legacy"], limit=10)
+
+    assert results is not None
+    assert [result["doc_id"] for result in results] == ["legacy-fix"]
+
+    await storage.close()