diff --git a/src/main/scala/li/cil/oc/common/EventHandler.scala b/src/main/scala/li/cil/oc/common/EventHandler.scala
index 9f73b65aa..848fe1ae1 100644
--- a/src/main/scala/li/cil/oc/common/EventHandler.scala
+++ b/src/main/scala/li/cil/oc/common/EventHandler.scala
@@ -22,6 +22,8 @@ import net.minecraft.network.{INetworkManager, NetLoginHandler}
 import net.minecraft.server.MinecraftServer
 import net.minecraft.tileentity.TileEntity
 import net.minecraftforge.common.MinecraftForge
+import net.minecraftforge.event.ForgeSubscribe
+import net.minecraftforge.event.world.WorldEvent
 
 import scala.collection.mutable
 import scala.concurrent.ExecutionContext.Implicits.global
@@ -181,4 +183,14 @@ object EventHandler extends ITickHandler with IConnectionHandler with ICraftingH
   }
 
   override def onSmelting(player: EntityPlayer, item: ItemStack) {}
+
+  @ForgeSubscribe
+  def onWorldUnload(e: WorldEvent.Unload) {
+    if (!e.world.isRemote) {
+      import scala.collection.convert.WrapAsScala._
+      e.world.loadedTileEntityList.collect {
+        case te: tileentity.traits.TileEntity => te.onChunkUnload()
+      }
+    }
+  }
 }
diff --git a/src/main/scala/li/cil/oc/common/Proxy.scala b/src/main/scala/li/cil/oc/common/Proxy.scala
index 3efdf533e..9cd18ce47 100644
--- a/src/main/scala/li/cil/oc/common/Proxy.scala
+++ b/src/main/scala/li/cil/oc/common/Proxy.scala
@@ -132,6 +132,7 @@ class Proxy {
     MinecraftForge.EVENT_BUS.register(AngelUpgradeHandler)
     MinecraftForge.EVENT_BUS.register(ChunkloaderUpgradeHandler)
     MinecraftForge.EVENT_BUS.register(ExperienceUpgradeHandler)
+    MinecraftForge.EVENT_BUS.register(EventHandler)
     MinecraftForge.EVENT_BUS.register(Loot)
     MinecraftForge.EVENT_BUS.register(RobotCommonHandler)
     MinecraftForge.EVENT_BUS.register(SaveHandler)
diff --git a/src/main/scala/li/cil/oc/common/tileentity/Adapter.scala b/src/main/scala/li/cil/oc/common/tileentity/Adapter.scala
index a6ffbd637..5804f7c39 100644
--- a/src/main/scala/li/cil/oc/common/tileentity/Adapter.scala
+++ b/src/main/scala/li/cil/oc/common/tileentity/Adapter.scala
@@ -51,31 +51,39 @@ class Adapter extends traits.Environment with Analyzable {
             case Some(newDriver) => blocks(d.ordinal()) match {
               case Some((oldEnvironment, driver)) =>
                 if (newDriver != driver) {
-                  // This is... odd. Maybe moved by some other mod?
-                  node.disconnect(oldEnvironment.node)
-                  val environment = newDriver.createEnvironment(world, x, y, z)
-                  blocks(d.ordinal()) = Some((environment, newDriver))
+                  // This is... odd. Maybe moved by some other mod? First, clean up.
+                  blocks(d.ordinal()) = None
                   updatingBlocks -= oldEnvironment
+                  blocksData(d.ordinal()) = None
+                  node.disconnect(oldEnvironment.node)
+
+                  // Then rebuild - if we have something.
+                  val environment = newDriver.createEnvironment(world, x, y, z)
+                  if (environment != null) {
+                    blocks(d.ordinal()) = Some((environment, newDriver))
+                    if (environment.canUpdate) {
+                      updatingBlocks += environment
+                    }
+                    blocksData(d.ordinal()) = Some(new BlockData(environment.getClass.getName, new NBTTagCompound()))
+                    node.connect(environment.node)
+                  }
+                } // else: the more things change, the more they stay the same.
+              case _ =>
+                // A challenger appears. Maybe.
+                val environment = newDriver.createEnvironment(world, x, y, z)
+                if (environment != null) {
+                  blocks(d.ordinal()) = Some((environment, newDriver))
                   if (environment.canUpdate) {
                     updatingBlocks += environment
                   }
+                  blocksData(d.ordinal()) match {
+                    case Some(data) if data.name == environment.getClass.getName =>
+                      environment.load(data.data)
+                    case _ =>
+                  }
                   blocksData(d.ordinal()) = Some(new BlockData(environment.getClass.getName, new NBTTagCompound()))
                   node.connect(environment.node)
-                } // else: the more things change, the more they stay the same.
-              case _ =>
-                // A challenger appears.
-                val environment = newDriver.createEnvironment(world, x, y, z)
-                blocks(d.ordinal()) = Some((environment, newDriver))
-                if (environment.canUpdate) {
-                  updatingBlocks += environment
                 }
-                blocksData(d.ordinal()) match {
-                  case Some(data) if data.name == environment.getClass.getName =>
-                    environment.load(data.data)
-                  case _ =>
-                }
-                blocksData(d.ordinal()) = Some(new BlockData(environment.getClass.getName, new NBTTagCompound()))
-                node.connect(environment.node)
             }
             case _ => blocks(d.ordinal()) match {
               case Some((environment, driver)) =>
diff --git a/src/main/scala/li/cil/oc/common/tileentity/ServerRack.scala b/src/main/scala/li/cil/oc/common/tileentity/ServerRack.scala
index 0023e7298..ed92ebd19 100644
--- a/src/main/scala/li/cil/oc/common/tileentity/ServerRack.scala
+++ b/src/main/scala/li/cil/oc/common/tileentity/ServerRack.scala
@@ -265,12 +265,16 @@ class ServerRack extends traits.PowerAcceptor with traits.Hub with traits.PowerB
 
   override protected def initialize() {
     super.initialize()
-    ServerRack.list += this -> Unit
+    if (isClient) {
+      ServerRack.list += this -> Unit
+    }
   }
 
   override protected def dispose() {
     super.dispose()
-    ServerRack.list -= this
+    if (isClient) {
+      ServerRack.list -= this
+    }
   }
 
   override def readFromNBT(nbt: NBTTagCompound) {
diff --git a/src/main/scala/li/cil/oc/server/component/Keyboard.scala b/src/main/scala/li/cil/oc/server/component/Keyboard.scala
index 49e34f507..d7faceb90 100644
--- a/src/main/scala/li/cil/oc/server/component/Keyboard.scala
+++ b/src/main/scala/li/cil/oc/server/component/Keyboard.scala
@@ -9,6 +9,7 @@ import li.cil.oc.api.network.{Message, Node, Visibility}
 import li.cil.oc.common.component
 import net.minecraft.entity.player.EntityPlayer
 import net.minecraftforge.common.MinecraftForge
+import net.minecraftforge.event.world.WorldEvent
 import net.minecraftforge.event.{Event, ForgeSubscribe}
 
 import scala.collection.mutable
@@ -45,6 +46,13 @@ class Keyboard(val owner: Container) extends component.ManagedComponent with api
     pressedKeys.remove(e.player)
   }
 
+  @ForgeSubscribe
+  def onWorldUnload(e: WorldEvent.Unload) {
+    try MinecraftForge.EVENT_BUS.unregister(this) catch {
+      case ignore: Throwable =>
+    }
+  }
+
   // ----------------------------------------------------------------------- //
 
   override def onConnect(node: Node) {
diff --git a/src/main/scala/li/cil/oc/server/component/machine/Machine.scala b/src/main/scala/li/cil/oc/server/component/machine/Machine.scala
index 61a925dc8..7a072cdbf 100644
--- a/src/main/scala/li/cil/oc/server/component/machine/Machine.scala
+++ b/src/main/scala/li/cil/oc/server/component/machine/Machine.scala
@@ -491,7 +491,7 @@ class Machine(val owner: Owner, constructor: Constructor[_ <: Architecture]) ext
   }
 
   override def onDisconnect(node: Node) {
-    if (node == this.node) {
+    if (node == this.node) this.synchronized {
       close()
       tmp.foreach(_.node.remove())
     }