--- a/net/minecraft/server/players/OldUsersConverter.java
+++ b/net/minecraft/server/players/OldUsersConverter.java
@@ -21,6 +21,9 @@
 import java.util.UUID;
 import javax.annotation.Nullable;
 import net.minecraft.core.UUIDUtil;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.NbtAccounter;
+import net.minecraft.nbt.NbtIo;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.dedicated.DedicatedServer;
 import net.minecraft.util.StringUtil;
@@ -62,7 +65,7 @@
             return new String[i];
         });
 
-        if (server.usesAuthentication()) {
+        if (server.usesAuthentication() || org.spigotmc.SpigotConfig.bungee) { // Spigot: bungee = online mode, for now.
             server.getProfileRepository().findProfilesByNames(astring, callback);
         } else {
             String[] astring1 = astring;
@@ -85,7 +88,7 @@
                 try {
                     gameprofilebanlist.load();
                 } catch (IOException ioexception) {
-                    OldUsersConverter.LOGGER.warn("Could not load existing file {}", gameprofilebanlist.getFile().getName(), ioexception);
+                    OldUsersConverter.LOGGER.warn("Could not load existing file {}", gameprofilebanlist.getFile().getName()); // CraftBukkit - don't print stacktrace
                 }
             }
 
@@ -143,7 +146,7 @@
                 try {
                     ipbanlist.load();
                 } catch (IOException ioexception) {
-                    OldUsersConverter.LOGGER.warn("Could not load existing file {}", ipbanlist.getFile().getName(), ioexception);
+                    OldUsersConverter.LOGGER.warn("Could not load existing file {}", ipbanlist.getFile().getName()); // CraftBukkit - don't print stacktrace
                 }
             }
 
@@ -184,7 +187,7 @@
                 try {
                     oplist.load();
                 } catch (IOException ioexception) {
-                    OldUsersConverter.LOGGER.warn("Could not load existing file {}", oplist.getFile().getName(), ioexception);
+                    OldUsersConverter.LOGGER.warn("Could not load existing file {}", oplist.getFile().getName()); // CraftBukkit - don't print stacktrace
                 }
             }
 
@@ -228,7 +231,7 @@
                 try {
                     whitelist.load();
                 } catch (IOException ioexception) {
-                    OldUsersConverter.LOGGER.warn("Could not load existing file {}", whitelist.getFile().getName(), ioexception);
+                    OldUsersConverter.LOGGER.warn("Could not load existing file {}", whitelist.getFile().getName()); // CraftBukkit - don't print stacktrace
                 }
             }
 
@@ -347,6 +350,30 @@
                         File file5 = new File(file, fileName + ".dat");
                         File file6 = new File(playerDataFolder, uuid + ".dat");
 
+                        // CraftBukkit start - Use old file name to seed lastKnownName
+                        CompoundTag root = null;
+
+                        try {
+                            root = NbtIo.readCompressed(new java.io.FileInputStream(file5), NbtAccounter.unlimitedHeap());
+                        } catch (Exception exception) {
+                            exception.printStackTrace();
+                        }
+
+                        if (root != null) {
+                            if (!root.contains("bukkit")) {
+                                root.put("bukkit", new CompoundTag());
+                            }
+                            CompoundTag data = root.getCompound("bukkit");
+                            data.putString("lastKnownName", fileName);
+
+                            try {
+                                NbtIo.writeCompressed(root, new java.io.FileOutputStream(file2));
+                            } catch (Exception exception) {
+                                exception.printStackTrace();
+                            }
+                       }
+                        // CraftBukkit end
+
                         OldUsersConverter.ensureDirectoryExists(playerDataFolder);
                         if (!file5.renameTo(file6)) {
                             throw new OldUsersConverter.ConversionError("Could not convert file for " + fileName);