diff --git a/Spigot-Server-Patches/0004-MC-Utils.patch b/Spigot-Server-Patches/0004-MC-Utils.patch
index 74da3f8683..af58e328b7 100644
--- a/Spigot-Server-Patches/0004-MC-Utils.patch
+++ b/Spigot-Server-Patches/0004-MC-Utils.patch
@@ -1,4 +1,4 @@
-From a3e63b2551a8b3dfabbc600ea7e5e72763ec6888 Mon Sep 17 00:00:00 2001
+From e4c4535575c0397de1e8a388e09428dd60947d13 Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Mon, 28 Mar 2016 20:55:47 -0400
 Subject: [PATCH] MC Utils
@@ -7,7 +7,7 @@ Collection of utils to help reduce NMS diff
 
 diff --git a/src/main/java/net/minecraft/server/MCUtil.java b/src/main/java/net/minecraft/server/MCUtil.java
 new file mode 100644
-index 0000000..8643312
+index 0000000..bcc8ee7
 --- /dev/null
 +++ b/src/main/java/net/minecraft/server/MCUtil.java
 @@ -0,0 +1,154 @@
@@ -23,7 +23,7 @@ index 0000000..8643312
 +
 +public final class MCUtil {
 +    private static final Pattern REPLACE_QUOTES = Pattern.compile("\"");
-+    private static final Executor asyncExecutor = Executors.newCachedThreadPool(new ThreadFactoryBuilder().setNameFormat("Paper Async Task Handler Thread - %1$d").build());
++    private static final Executor asyncExecutor = Executors.newSingleThreadExecutor(new ThreadFactoryBuilder().setNameFormat("Paper Async Task Handler Thread - %1$d").build());
 +
 +    private MCUtil() {}
 +
diff --git a/Spigot-Server-Patches/0156-Optimize-UserCache-Thread-Safe.patch b/Spigot-Server-Patches/0156-Optimize-UserCache-Thread-Safe.patch
index 7429ac2f1b..fa9d4a6c0a 100644
--- a/Spigot-Server-Patches/0156-Optimize-UserCache-Thread-Safe.patch
+++ b/Spigot-Server-Patches/0156-Optimize-UserCache-Thread-Safe.patch
@@ -1,4 +1,4 @@
-From a16fb3ba3001e1a330a3b2aeae75a89870d69d33 Mon Sep 17 00:00:00 2001
+From fadf46bd5f5d74c2a61e95601b3bd3704b16d71b Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Mon, 16 May 2016 20:47:41 -0400
 Subject: [PATCH] Optimize UserCache / Thread Safe
@@ -23,9 +23,18 @@ index ec9f037..7e7ec23 100644
          // Spigot end
      }
 diff --git a/src/main/java/net/minecraft/server/UserCache.java b/src/main/java/net/minecraft/server/UserCache.java
-index 5cc2731..4fde2de 100644
+index 5cc2731..ca20b3d 100644
 --- a/src/main/java/net/minecraft/server/UserCache.java
 +++ b/src/main/java/net/minecraft/server/UserCache.java
+@@ -108,7 +108,7 @@ public class UserCache {
+         this.a(gameprofile, (Date) null);
+     }
+ 
+-    private void a(GameProfile gameprofile, Date date) {
++    private synchronized void a(GameProfile gameprofile, Date date) { // Paper - synchronize
+         UUID uuid = gameprofile.getId();
+ 
+         if (date == null) {
 @@ -122,8 +122,9 @@ public class UserCache {
          String s = gameprofile.getName().toLowerCase(Locale.ROOT);
          UserCache.UserCacheEntry usercache_usercacheentry = new UserCache.UserCacheEntry(gameprofile, date, null);
@@ -37,6 +46,24 @@ index 5cc2731..4fde2de 100644
  
              this.d.remove(usercache_usercacheentry1.a().getName().toLowerCase(Locale.ROOT));
              this.f.remove(gameprofile);
+@@ -136,7 +137,7 @@ public class UserCache {
+     }
+ 
+     @Nullable
+-    public GameProfile getProfile(String s) {
++    public synchronized GameProfile getProfile(String s) { // Paper - synchronize
+         String s1 = s.toLowerCase(Locale.ROOT);
+         UserCache.UserCacheEntry usercache_usercacheentry = (UserCache.UserCacheEntry) this.d.get(s1);
+ 
+@@ -165,7 +166,7 @@ public class UserCache {
+         return usercache_usercacheentry == null ? null : usercache_usercacheentry.a();
+     }
+ 
+-    public String[] a() {
++    public synchronized String[] a() { // Paper - synchronize
+         ArrayList arraylist = Lists.newArrayList(this.d.keySet());
+ 
+         return (String[]) arraylist.toArray(new String[arraylist.size()]);
 @@ -227,8 +228,15 @@ public class UserCache {
  
      }
@@ -48,7 +75,7 @@ index 5cc2731..4fde2de 100644
 +    public void c(boolean asyncSave) {
 +        // Paper end
          String s = this.b.toJson(this.a(org.spigotmc.SpigotConfig.userCacheCap));
-+        Runnable save = () -> { // Paper - ensure only 1 file is writing at same time by syncing to the FD // ¯\_(ツ)_/¯
++        Runnable save = () -> { // Paper - ensure only 1 file is writing at same time by syncing to the FD
 +
          BufferedWriter bufferedwriter = null;
  
@@ -58,7 +85,7 @@ index 5cc2731..4fde2de 100644
              IOUtils.closeQuietly(bufferedwriter);
          }
 +        // Paper start
-+        };
++        }};
 +        if (asyncSave) {
 +            MCUtil.scheduleAsyncTask(save);
 +        } else {