diff --git a/src/main/java/net/frozenorb/apiv3/APIv3.java b/src/main/java/net/frozenorb/apiv3/APIv3.java
index 45f89bd..ccfe55f 100644
--- a/src/main/java/net/frozenorb/apiv3/APIv3.java
+++ b/src/main/java/net/frozenorb/apiv3/APIv3.java
@@ -103,6 +103,8 @@ import net.frozenorb.apiv3.serialization.jackson.UuidJsonDeserializer;
 import net.frozenorb.apiv3.serialization.jackson.UuidJsonSerializer;
 import net.frozenorb.apiv3.serialization.mongodb.UuidCodecProvider;
 import net.frozenorb.apiv3.util.EmailUtils;
+import net.frozenorb.apiv3.util.MojangUtils;
+import net.frozenorb.apiv3.util.SyncUtils;
 import org.bson.Document;
 import org.bson.codecs.BsonValueCodecProvider;
 import org.bson.codecs.DocumentCodecProvider;
@@ -137,6 +139,24 @@ public final class APIv3 extends AbstractVerticle {
 		setupMetrics();
 		setupHttpServer();
 
+		User.findAll((users, error) -> {
+			if (error != null) {
+				error.printStackTrace();
+				return;
+			}
+
+			for (User user : users) {
+				String currentUsername = SyncUtils.runBlocking(v -> MojangUtils.getName(user.getId(), v));
+				String lastUsername = user.getLastUsername();
+
+				if (!currentUsername.equals(lastUsername)) {
+					SyncUtils.<Void>runBlocking(v -> user.checkNameCollisions(v));
+				}
+
+				log.info(user.getLastUsername() + " - " + user.getLastSeenAt());
+			}
+		});
+
         /*V2Importer converter = new V2Importer("mongodb://158.69.126.126", "minehq");
 
         converter.startImport((ignored, error) -> {
diff --git a/src/main/java/net/frozenorb/apiv3/model/User.java b/src/main/java/net/frozenorb/apiv3/model/User.java
index c5ab036..8fe7d01 100644
--- a/src/main/java/net/frozenorb/apiv3/model/User.java
+++ b/src/main/java/net/frozenorb/apiv3/model/User.java
@@ -63,6 +63,10 @@ public final class User {
 	@Getter private Instant firstSeenAt;
 	@Getter private boolean online;
 
+	public static void findAll(SingleResultCallback<List<User>> callback) {
+		usersCollection.find().sort(new Document("lastSeenAt", -1)).into(new LinkedList<>(), SyncUtils.vertxWrap(callback));
+	}
+
 	public static void findById(String id, SingleResultCallback<User> callback) {
 		try {
 			findById(UuidUtils.parseUuid(id), callback);
@@ -79,7 +83,6 @@ public final class User {
 		}
 	}
 
-
 	public static void findOrCreateById(UUID id, String username, SingleResultCallback<User> callback) {
 		if (!UuidUtils.isAcceptableUuid(id)) {
 			callback.onResult(null, null);