diff --git a/src/main/java/com/atsuishio/superbwarfare/entity/Blu43Entity.java b/src/main/java/com/atsuishio/superbwarfare/entity/Blu43Entity.java
index 8d18a6072..80cc74611 100644
--- a/src/main/java/com/atsuishio/superbwarfare/entity/Blu43Entity.java
+++ b/src/main/java/com/atsuishio/superbwarfare/entity/Blu43Entity.java
@@ -125,8 +125,11 @@ public class Blu43Entity extends Entity implements GeoEntity, OwnableEntity {
         } else {
             String s = compound.getString("Owner");
 
-            assert this.getServer() != null;
-            uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            if (this.getServer() == null) {
+                uuid = UUID.fromString(s);
+            } else {
+                uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            }
         }
 
         if (uuid != null) {
diff --git a/src/main/java/com/atsuishio/superbwarfare/entity/ClaymoreEntity.java b/src/main/java/com/atsuishio/superbwarfare/entity/ClaymoreEntity.java
index 681cea56b..2a1fcb4b0 100644
--- a/src/main/java/com/atsuishio/superbwarfare/entity/ClaymoreEntity.java
+++ b/src/main/java/com/atsuishio/superbwarfare/entity/ClaymoreEntity.java
@@ -130,8 +130,11 @@ public class ClaymoreEntity extends Entity implements GeoEntity, OwnableEntity {
         } else {
             String s = compound.getString("Owner");
 
-            assert this.getServer() != null;
-            uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            if (this.getServer() == null) {
+                uuid = UUID.fromString(s);
+            } else {
+                uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            }
         }
 
         if (uuid != null) {
diff --git a/src/main/java/com/atsuishio/superbwarfare/entity/Tm62Entity.java b/src/main/java/com/atsuishio/superbwarfare/entity/Tm62Entity.java
index 5f53e4d4d..ac52d6441 100644
--- a/src/main/java/com/atsuishio/superbwarfare/entity/Tm62Entity.java
+++ b/src/main/java/com/atsuishio/superbwarfare/entity/Tm62Entity.java
@@ -134,8 +134,11 @@ public class Tm62Entity extends Entity implements GeoEntity, OwnableEntity {
         } else {
             String s = compound.getString("Owner");
 
-            assert this.getServer() != null;
-            uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            if (this.getServer() == null) {
+                uuid = UUID.fromString(s);
+            } else {
+                uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            }
         }
 
         if (uuid != null) {
diff --git a/src/main/java/com/atsuishio/superbwarfare/entity/projectile/C4Entity.java b/src/main/java/com/atsuishio/superbwarfare/entity/projectile/C4Entity.java
index bdd8142ee..266a8b9d4 100644
--- a/src/main/java/com/atsuishio/superbwarfare/entity/projectile/C4Entity.java
+++ b/src/main/java/com/atsuishio/superbwarfare/entity/projectile/C4Entity.java
@@ -144,8 +144,11 @@ public class C4Entity extends Entity implements GeoEntity, OwnableEntity {
         } else {
             String s = compound.getString("Owner");
 
-            assert this.getServer() != null;
-            uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            if (this.getServer() == null) {
+                uuid = UUID.fromString(s);
+            } else {
+                uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            }
         }
 
         if (uuid != null) {
diff --git a/src/main/java/com/atsuishio/superbwarfare/entity/vehicle/Hpj11Entity.java b/src/main/java/com/atsuishio/superbwarfare/entity/vehicle/Hpj11Entity.java
index 1cf6a7db4..95571746b 100644
--- a/src/main/java/com/atsuishio/superbwarfare/entity/vehicle/Hpj11Entity.java
+++ b/src/main/java/com/atsuishio/superbwarfare/entity/vehicle/Hpj11Entity.java
@@ -131,8 +131,11 @@ public class Hpj11Entity extends ContainerMobileVehicleEntity implements GeoEnti
         } else {
             String s = compound.getString("Owner");
 
-            assert this.getServer() != null;
-            uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            if (this.getServer() == null) {
+                uuid = UUID.fromString(s);
+            } else {
+                uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            }
         }
 
         if (uuid != null) {
diff --git a/src/main/java/com/atsuishio/superbwarfare/entity/vehicle/LaserTowerEntity.java b/src/main/java/com/atsuishio/superbwarfare/entity/vehicle/LaserTowerEntity.java
index ecdc57e83..979adc217 100644
--- a/src/main/java/com/atsuishio/superbwarfare/entity/vehicle/LaserTowerEntity.java
+++ b/src/main/java/com/atsuishio/superbwarfare/entity/vehicle/LaserTowerEntity.java
@@ -110,8 +110,11 @@ public class LaserTowerEntity extends VehicleEntity implements GeoEntity, Ownabl
         } else {
             String s = compound.getString("Owner");
 
-            assert this.getServer() != null;
-            uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            if (this.getServer() == null) {
+                uuid = UUID.fromString(s);
+            } else {
+                uuid = OldUsersConverter.convertMobOwnerIfNecessary(this.getServer(), s);
+            }
         }
 
         if (uuid != null) {