diff --git a/Utils/NginxStoppedCleaner.cs b/Utils/NginxStoppedCleaner.cs
index 8503040..dc33356 100644
--- a/Utils/NginxStoppedCleaner.cs
+++ b/Utils/NginxStoppedCleaner.cs
@@ -1,42 +1,43 @@
 using System.IO;
 using System.Security.Cryptography.X509Certificates;
+using System.Threading;
 using Sheas_Cealer.Consts;
 
 namespace Sheas_Cealer.Utils
 {
     internal static class NginxStoppedCleaner
     {
-        private static bool IsCleaning = false;
+        private static readonly object IsCleaningLock = new();
 
         internal static void Clean()
         {
-            if (IsCleaning)
+            if (!Monitor.TryEnter(IsCleaningLock))
                 return;
 
-            IsCleaning = true;
+            try
+            {
+                string hostsContent = File.ReadAllText(MainConst.HostsConfPath);
+                int hostsConfStartIndex = hostsContent.IndexOf(MainConst.HostsConfStartMarker);
+                int hostsConfEndIndex = hostsContent.LastIndexOf(MainConst.HostsConfEndMarker);
 
-            string hostsContent = File.ReadAllText(MainConst.HostsConfPath);
-            int hostsConfStartIndex = hostsContent.IndexOf(MainConst.HostsConfStartMarker);
-            int hostsConfEndIndex = hostsContent.LastIndexOf(MainConst.HostsConfEndMarker);
+                if (hostsConfStartIndex != -1 && hostsConfEndIndex != -1)
+                    File.WriteAllText(MainConst.HostsConfPath, hostsContent.Remove(hostsConfStartIndex, hostsConfEndIndex - hostsConfStartIndex + MainConst.HostsConfEndMarker.Length));
 
-            if (hostsConfStartIndex != -1 && hostsConfEndIndex != -1)
-                File.WriteAllText(MainConst.HostsConfPath, hostsContent.Remove(hostsConfStartIndex, hostsConfEndIndex - hostsConfStartIndex + MainConst.HostsConfEndMarker.Length));
+                using X509Store certStore = new(StoreName.Root, StoreLocation.CurrentUser, OpenFlags.ReadWrite);
 
-            using X509Store certStore = new(StoreName.Root, StoreLocation.CurrentUser, OpenFlags.ReadWrite);
+                foreach (X509Certificate2 storedCert in certStore.Certificates)
+                    if (storedCert.Subject == MainConst.NginxRootCertSubjectName)
+                        while (true)
+                            try
+                            {
+                                certStore.Remove(storedCert);
+                                break;
+                            }
+                            catch { }
 
-            foreach (X509Certificate2 storedCert in certStore.Certificates)
-                if (storedCert.Subject == MainConst.NginxRootCertSubjectName)
-                    while (true)
-                        try
-                        {
-                            certStore.Remove(storedCert);
-                            break;
-                        }
-                        catch { }
-
-            certStore.Close();
-
-            IsCleaning = false;
+                certStore.Close();
+            }
+            finally { Monitor.Exit(IsCleaningLock); }
         }
     }
 }
\ No newline at end of file