diff --git a/rust/src/smb/smb1.rs b/rust/src/smb/smb1.rs
index b305b00427..a2044728dd 100644
--- a/rust/src/smb/smb1.rs
+++ b/rust/src/smb/smb1.rs
@@ -710,7 +710,7 @@ pub fn smb1_write_request_record<'b>(state: &mut SMBState, r: &SmbRecord<'b>)
 
             let file_name = match state.guid2name_map.get(&file_fid) {
                 Some(n) => n.to_vec(),
-                None => Vec::new(),
+                None => b"<unknown>".to_vec(),
             };
             let found = match state.get_file_tx_by_fuid(&file_fid, STREAM_TOSERVER) {
                 Some((tx, files, flags)) => {
diff --git a/rust/src/smb/smb2.rs b/rust/src/smb/smb2.rs
index 86a575fa39..83094ddf94 100644
--- a/rust/src/smb/smb2.rs
+++ b/rust/src/smb/smb2.rs
@@ -170,7 +170,7 @@ pub fn smb2_read_response_record<'b>(state: &mut SMBState, r: &Smb2Record<'b>)
                 } else {
                     let file_name = match state.guid2name_map.get(&file_guid) {
                         Some(n) => { n.to_vec() },
-                        None => { Vec::new() },
+                        None => { b"<unknown>".to_vec() },
                     };
                     let (tx, files, flags) = state.new_file_tx(&file_guid, &file_name, STREAM_TOCLIENT);
                     if let Some(SMBTransactionTypeData::FILE(ref mut tdf)) = tx.type_data {