diff --git a/src/fs.rs b/src/fs.rs
index 2c79199cf..bc3ccf64f 100644
--- a/src/fs.rs
+++ b/src/fs.rs
@@ -144,17 +144,21 @@ pub fn new(locking_mode: LockingMode, file_path: &wstr) -> std::io::Result<Self>
         // This is required to avoid racing modifications by other threads/processes.
         let dir_fd = wopen_cloexec(dir_path, OFlag::O_RDONLY, Mode::empty())?;
 
-        // Try locking the directory. Retry if locking was interrupted.
-        while unsafe { libc::flock(dir_fd.as_raw_fd(), locking_mode.flock_op()) } == -1 {
-            let err = std::io::Error::last_os_error();
-            if err.kind() != std::io::ErrorKind::Interrupted {
-                return Err(err);
+        {
+            // Cygwin's `flock` is currently not thread safe (#11933)
+            #[cfg(cygwin)]
+            static FLOCK_LOCK: std::sync::Mutex<()> = std::sync::Mutex::new(());
+            #[cfg(cygwin)]
+            let _lock = FLOCK_LOCK.lock().unwrap();
+
+            // Try locking the directory. Retry if locking was interrupted.
+            while unsafe { libc::flock(dir_fd.as_raw_fd(), locking_mode.flock_op()) } == -1 {
+                let err = std::io::Error::last_os_error();
+                if err.kind() != std::io::ErrorKind::Interrupted {
+                    return Err(err);
+                }
             }
         }
-        #[cfg(cygwin)]
-        // Prevents error 14 "Bad Addr" on Windows (#11933). If the error happens
-        // the process appears deadlocked
-        std::thread::sleep(std::time::Duration::from_nanos(1));
 
         // Open the data file
         let data_file = wopen_cloexec(file_path, locking_mode.file_flags(), LOCKED_FILE_MODE)?;
diff --git a/src/history/history.rs b/src/history/history.rs
index 1b7ce5f39..7780921a9 100644
--- a/src/history/history.rs
+++ b/src/history/history.rs
@@ -2015,11 +2015,6 @@ fn pound_on_history(item_count: usize, idx: usize) -> Arc<History> {
     fn test_history_races() {
         let _cleanup = test_init();
 
-        // Fail nearly every time on Cygwin (probably caused by flock issue, see #11933)
-        if cfg!(cygwin) {
-            return;
-        }
-
         let tmp_path = std::env::current_dir()
             .unwrap()
             .join("history-races-test-balloon");