diff --git a/proxmox-sys/src/process_locker.rs b/proxmox-sys/src/process_locker.rs
index 4874da80..65d2793a 100644
--- a/proxmox-sys/src/process_locker.rs
+++ b/proxmox-sys/src/process_locker.rs
@@ -112,6 +112,7 @@ impl ProcessLocker {
             .create(true)
             .read(true)
             .write(true)
+            .truncate(false)
             .open(lockfile)?;
 
         Ok(Arc::new(Mutex::new(Self {