diff --git a/src/dir.rs b/src/dir.rs
index 0fc343b..f4a0520 100644
--- a/src/dir.rs
+++ b/src/dir.rs
@@ -298,6 +298,12 @@ impl <'a, T: ReadWriteSeek + 'a> Dir<'a, T> {
         trace!("moving {} to {}", src_name, dst_name);
         // find existing file
         let e = self.find_entry(src_name, None, None)?;
+        // check if destionation filename is unused
+        let mut short_name_gen = ShortNameGenerator::new(dst_name);
+        let r = dst_dir.find_entry(dst_name, None, Some(&mut short_name_gen));
+        if r.is_ok() {
+            return Err(io::Error::new(ErrorKind::AlreadyExists, "destination file already exists"))
+        }
         // free long and short name entries
         let mut stream = self.stream.clone();
         stream.seek(SeekFrom::Start(e.offset_range.0 as u64))?;
@@ -309,12 +315,6 @@ impl <'a, T: ReadWriteSeek + 'a> Dir<'a, T> {
             stream.seek(SeekFrom::Current(-(DIR_ENTRY_SIZE as i64)))?;
             data.serialize(&mut stream)?;
         }
-        // check if destionation filename is unused
-        let mut short_name_gen = ShortNameGenerator::new(dst_name);
-        let r = dst_dir.find_entry(dst_name, None, Some(&mut short_name_gen));
-        if r.is_ok() {
-            return Err(io::Error::new(ErrorKind::AlreadyExists, "destination file already exists"))
-        }
         // save new directory entry
         let short_name = short_name_gen.generate()?;
         let sfn_entry = e.data.renamed(short_name);
diff --git a/tests/write.rs b/tests/write.rs
index 05d18cd..87397e4 100644
--- a/tests/write.rs
+++ b/tests/write.rs
@@ -271,6 +271,11 @@ fn test_rename_file(fs: FileSystem) {
     file.read_to_end(&mut buf).unwrap();
     assert_eq!(str::from_utf8(&buf).unwrap(), TEST_STR2);
 
+    assert!(root_dir.rename("moved-file.txt", &root_dir, "short.txt").is_err());
+    let entries = root_dir.iter().map(|r| r.unwrap()).collect::<Vec<_>>();
+    let names = entries.iter().map(|r| r.file_name()).collect::<Vec<_>>();
+    assert_eq!(names, ["long.txt", "short.txt", "very", "very-long-dir-name", "moved-file.txt"]);
+
     let new_stats = fs.stats().unwrap();
     assert_eq!(new_stats.free_clusters(), stats.free_clusters());
 }