diff --git a/README.md b/README.md
index 8653509..1a21b35 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,7 @@ snac2nex -s /path/to/snac/storage -t /path/to/nex -u user1 -u user2
           Post filenames format
 
           * escaped with `%%`
+          * be careful when removing seconds, as it may cause overwrite collisions
 
           [default: %H:%M:%S]
 
diff --git a/src/config.rs b/src/config.rs
index 5df54ea..b9e8a83 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -36,6 +36,7 @@ pub struct Config {
     /// Post filenames format
     ///
     /// * escaped with `%%`
+    /// * be careful when removing seconds, as it may cause overwrite collisions
     #[arg(long, default_value_t = String::from("%H:%M:%S"))]
     pub format_filename: String,