diff --git a/src/main/java/dan200/computercraft/shared/command/ClientCommands.java b/src/main/java/dan200/computercraft/shared/command/ClientCommands.java
index c16b3fdd1..0477c46ad 100644
--- a/src/main/java/dan200/computercraft/shared/command/ClientCommands.java
+++ b/src/main/java/dan200/computercraft/shared/command/ClientCommands.java
@@ -7,11 +7,13 @@
 
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.shared.util.IDAssigner;
+import net.minecraft.server.MinecraftServer;
 import net.minecraft.util.Util;
 import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.client.event.ClientChatEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
+import net.minecraftforge.fml.server.ServerLifecycleHooks;
 
 import java.io.File;
 
@@ -35,6 +37,9 @@ public static void onClientSendMessage( ClientChatEvent event )
         // Emulate the command on the client side
         if( event.getMessage().startsWith( OPEN_COMPUTER ) )
         {
+            MinecraftServer server = ServerLifecycleHooks.getCurrentServer();
+            if( server == null || server.isDedicatedServer() ) return;
+
             event.setCanceled( true );
 
             String idStr = event.getMessage().substring( OPEN_COMPUTER.length() ).trim();
diff --git a/src/main/java/dan200/computercraft/shared/network/NetworkHandler.java b/src/main/java/dan200/computercraft/shared/network/NetworkHandler.java
index 3d4fd5143..c66465340 100644
--- a/src/main/java/dan200/computercraft/shared/network/NetworkHandler.java
+++ b/src/main/java/dan200/computercraft/shared/network/NetworkHandler.java
@@ -21,7 +21,6 @@
 import net.minecraftforge.fml.network.NetworkRegistry;
 import net.minecraftforge.fml.network.PacketDistributor;
 import net.minecraftforge.fml.network.simple.SimpleChannel;
-import net.minecraftforge.fml.server.ServerLifecycleHooks;
 
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -68,10 +67,7 @@ public static void sendToPlayer( PlayerEntity player, NetworkMessage packet )
 
     public static void sendToAllPlayers( NetworkMessage packet )
     {
-        for( ServerPlayerEntity player : ServerLifecycleHooks.getCurrentServer().getPlayerList().getPlayers() )
-        {
-            sendToPlayer( player, packet );
-        }
+        network.send( PacketDistributor.ALL.noArg(), packet );
     }
 
     public static void sendToServer( NetworkMessage packet )
diff --git a/src/main/java/dan200/computercraft/shared/peripheral/speaker/TileSpeaker.java b/src/main/java/dan200/computercraft/shared/peripheral/speaker/TileSpeaker.java
index 600190867..89e928503 100644
--- a/src/main/java/dan200/computercraft/shared/peripheral/speaker/TileSpeaker.java
+++ b/src/main/java/dan200/computercraft/shared/peripheral/speaker/TileSpeaker.java
@@ -47,7 +47,10 @@ public void tick()
     public void setRemoved()
     {
         super.setRemoved();
-        NetworkHandler.sendToAllPlayers( new SpeakerStopClientMessage( source ) );
+        if( level != null && !level.isClientSide )
+        {
+            NetworkHandler.sendToAllPlayers( new SpeakerStopClientMessage( source ) );
+        }
     }
 
     @Nonnull