diff --git a/bukkit/src/main/java/com/github/games647/fastlogin/bukkit/command/PremiumCommand.java b/bukkit/src/main/java/com/github/games647/fastlogin/bukkit/command/PremiumCommand.java
index 28974bae..761d838f 100644
--- a/bukkit/src/main/java/com/github/games647/fastlogin/bukkit/command/PremiumCommand.java
+++ b/bukkit/src/main/java/com/github/games647/fastlogin/bukkit/command/PremiumCommand.java
@@ -40,27 +40,27 @@ public class PremiumCommand extends ToggleCommand {
             return;
         }
 
-            UUID id = ((Player) sender).getUniqueId();
-            if (plugin.getConfig().getBoolean("premium-warning") && !plugin.getCore().getPendingConfirms().contains(id)) {
-                sender.sendMessage(plugin.getCore().getMessage("premium-warning"));
-                plugin.getCore().getPendingConfirms().add(id);
-                return;
-            }
+        UUID id = ((Player) sender).getUniqueId();
+        if (plugin.getConfig().getBoolean("premium-warning") && !plugin.getCore().getPendingConfirms().contains(id)) {
+            sender.sendMessage(plugin.getCore().getMessage("premium-warning"));
+            plugin.getCore().getPendingConfirms().add(id);
+            return;
+        }
 
-            plugin.getCore().getPendingConfirms().remove(id);
-            //todo: load async
-            StoredProfile profile = plugin.getCore().getStorage().loadProfile(sender.getName());
-            if (profile.isPremium()) {
-                plugin.getCore().sendLocaleMessage("already-exists", sender);
-            } else {
-                //todo: resolve uuid
-                profile.setPremium(true);
-                plugin.getScheduler().runAsync(() -> {
-                    plugin.getCore().getStorage().save(profile);
-                });
+        plugin.getCore().getPendingConfirms().remove(id);
+        //todo: load async
+        StoredProfile profile = plugin.getCore().getStorage().loadProfile(sender.getName());
+        if (profile.isPremium()) {
+            plugin.getCore().sendLocaleMessage("already-exists", sender);
+        } else {
+            //todo: resolve uuid
+            profile.setPremium(true);
+            plugin.getScheduler().runAsync(() -> {
+                plugin.getCore().getStorage().save(profile);
+            });
 
-                plugin.getCore().sendLocaleMessage("add-premium", sender);
-            }
+            plugin.getCore().sendLocaleMessage("add-premium", sender);
+        }
     }
 
     private void onPremiumOther(CommandSender sender, Command command, String[] args) {
diff --git a/core/src/main/java/com/github/games647/fastlogin/core/AuthStorage.java b/core/src/main/java/com/github/games647/fastlogin/core/AuthStorage.java
index 904d5921..8dad3a72 100644
--- a/core/src/main/java/com/github/games647/fastlogin/core/AuthStorage.java
+++ b/core/src/main/java/com/github/games647/fastlogin/core/AuthStorage.java
@@ -184,31 +184,36 @@ public class AuthStorage {
         try (Connection con = dataSource.getConnection()) {
             String uuid = playerProfile.getOptId().map(UUIDAdapter::toMojangId).orElse(null);
 
-            if (playerProfile.isSaved()) {
-                try (PreparedStatement saveStmt = con.prepareStatement(UPDATE_PROFILE)) {
-                    saveStmt.setString(1, uuid);
-                    saveStmt.setString(2, playerProfile.getName());
-                    saveStmt.setBoolean(3, playerProfile.isPremium());
-                    saveStmt.setString(4, playerProfile.getLastIp());
+            playerProfile.getSaveLock().lock();
+            try {
+                if (playerProfile.isSaved()) {
+                    try (PreparedStatement saveStmt = con.prepareStatement(UPDATE_PROFILE)) {
+                        saveStmt.setString(1, uuid);
+                        saveStmt.setString(2, playerProfile.getName());
+                        saveStmt.setBoolean(3, playerProfile.isPremium());
+                        saveStmt.setString(4, playerProfile.getLastIp());
 
-                    saveStmt.setLong(5, playerProfile.getRowId());
-                    saveStmt.execute();
-                }
-            } else {
-                try (PreparedStatement saveStmt = con.prepareStatement(INSERT_PROFILE, RETURN_GENERATED_KEYS)) {
-                    saveStmt.setString(1, uuid);
+                        saveStmt.setLong(5, playerProfile.getRowId());
+                        saveStmt.execute();
+                    }
+                } else {
+                    try (PreparedStatement saveStmt = con.prepareStatement(INSERT_PROFILE, RETURN_GENERATED_KEYS)) {
+                        saveStmt.setString(1, uuid);
 
-                    saveStmt.setString(2, playerProfile.getName());
-                    saveStmt.setBoolean(3, playerProfile.isPremium());
-                    saveStmt.setString(4, playerProfile.getLastIp());
+                        saveStmt.setString(2, playerProfile.getName());
+                        saveStmt.setBoolean(3, playerProfile.isPremium());
+                        saveStmt.setString(4, playerProfile.getLastIp());
 
-                    saveStmt.execute();
-                    try (ResultSet generatedKeys = saveStmt.getGeneratedKeys()) {
-                        if (generatedKeys != null && generatedKeys.next()) {
-                            playerProfile.setRowId(generatedKeys.getInt(1));
+                        saveStmt.execute();
+                        try (ResultSet generatedKeys = saveStmt.getGeneratedKeys()) {
+                            if (generatedKeys != null && generatedKeys.next()) {
+                                playerProfile.setRowId(generatedKeys.getInt(1));
+                            }
                         }
                     }
                 }
+            } finally {
+                playerProfile.getSaveLock().unlock();
             }
         } catch (SQLException ex) {
             core.getPlugin().getLog().error("Failed to save playerProfile {}", playerProfile, ex);
diff --git a/core/src/main/java/com/github/games647/fastlogin/core/StoredProfile.java b/core/src/main/java/com/github/games647/fastlogin/core/StoredProfile.java
index 786a174d..389ea373 100644
--- a/core/src/main/java/com/github/games647/fastlogin/core/StoredProfile.java
+++ b/core/src/main/java/com/github/games647/fastlogin/core/StoredProfile.java
@@ -5,10 +5,12 @@ import com.github.games647.craftapi.model.Profile;
 import java.time.Instant;
 import java.util.Optional;
 import java.util.UUID;
+import java.util.concurrent.locks.ReentrantLock;
 
 public class StoredProfile extends Profile {
 
     private long rowId;
+    private final ReentrantLock saveLock = new ReentrantLock();
 
     private boolean premium;
     private String lastIp;
@@ -27,6 +29,10 @@ public class StoredProfile extends Profile {
         this(-1, uuid, playerName, premium, lastIp, Instant.now());
     }
 
+    public ReentrantLock getSaveLock() {
+        return saveLock;
+    }
+
     public synchronized boolean isSaved() {
         return rowId >= 0;
     }