diff --git a/buster/completers/base.py b/buster/completers/base.py
index 14071d7..0d624cd 100644
--- a/buster/completers/base.py
+++ b/buster/completers/base.py
@@ -88,7 +88,7 @@ def to_json(self, columns_to_ignore: Optional[list[str]] = None) -> Any:
 
         def encode_df(df: pd.DataFrame) -> dict:
             if columns_to_ignore is not None:
-                df = df.drop(columns=columns_to_ignore)
+                df = df.drop(columns=columns_to_ignore, errors='ignore')
             return df.to_json(orient="index")
 
         custom_encoder = {