diff --git a/.python-version b/.python-version
index 8531a3b..7ecaebe 100644
--- a/.python-version
+++ b/.python-version
@@ -1 +1 @@
-3.12.2
+system@3.13.1
diff --git a/requirements-dev.lock b/requirements-dev.lock
index d795436..8f23096 100644
--- a/requirements-dev.lock
+++ b/requirements-dev.lock
@@ -6,6 +6,5 @@
 #   features: []
 #   all-features: false
 #   with-sources: false
-#   generate-hashes: false
 
 -e file:.
diff --git a/requirements.lock b/requirements.lock
index d795436..8f23096 100644
--- a/requirements.lock
+++ b/requirements.lock
@@ -6,6 +6,5 @@
 #   features: []
 #   all-features: false
 #   with-sources: false
-#   generate-hashes: false
 
 -e file:.
diff --git a/src/browser_history_merger/__init__.py b/src/browser_history_merger/__init__.py
index a44a76e..493b9fe 100644
--- a/src/browser_history_merger/__init__.py
+++ b/src/browser_history_merger/__init__.py
@@ -188,7 +188,7 @@ def get_db_type(cur: sqlite3.Cursor) -> Literal["firefox", "chromium"]:
     return db_type
 
 
-def get_browser_info(root_cur: sqlite3.Cursor, name: str) -> tuple[int, int, str]:
+def get_browser_info(root_cur: sqlite3.Cursor, name: str) -> tuple[int, int, str] | None:
     res = root_cur.execute(
         """
         SELECT
@@ -202,7 +202,10 @@ def get_browser_info(root_cur: sqlite3.Cursor, name: str) -> tuple[int, int, str
         """,
         (name,),
     )
-    browser_id, visits_time_max, database_path = res.fetchone()
+    res_one = res.fetchone()
+    if res_one is None:
+        return None
+    browser_id, visits_time_max, database_path = res_one
     return (browser_id, visits_time_max, database_path)
 
 
@@ -250,7 +253,13 @@ def add_db(
     root_con: sqlite3.Connection, root_cur: sqlite3.Cursor, args: argparse.Namespace
 ):
     print("Add history to root db")
-    browser_id, visits_time_max, database_path = get_browser_info(root_cur, args.name)
+    browser_info = get_browser_info(root_cur, args.name)
+    if browser_info is None:
+        print(f"browser {args.name} is not registered to the database")
+        logging.debug("Cleaning up (closing db connection)")
+        root_con.close()
+        exit(1)
+    browser_id, visits_time_max, database_path = browser_info
     logging.info(f"{browser_id=}, {visits_time_max=}")
 
     logging.info(f"Source: {database_path}")