--- a/net/minecraft/server/players/NameReferencingFileConverter.java
+++ b/net/minecraft/server/players/NameReferencingFileConverter.java
@@ -27,6 +27,11 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+// CraftBukkit start
+import net.minecraft.nbt.NBTCompressedStreamTools;
+import net.minecraft.nbt.NBTTagCompound;
+// CraftBukkit end
+
 public class NameReferencingFileConverter {
 
     static final Logger LOGGER = LogManager.getLogger();
@@ -87,7 +92,7 @@
                 try {
                     gameprofilebanlist.load();
                 } catch (IOException ioexception) {
-                    NameReferencingFileConverter.LOGGER.warn("Could not load existing file {}", gameprofilebanlist.b().getName(), ioexception);
+                    NameReferencingFileConverter.LOGGER.warn("Could not load existing file {}", gameprofilebanlist.b().getName()); // CraftBukkit - don't print stacktrace
                 }
             }
 
@@ -145,7 +150,7 @@
                 try {
                     ipbanlist.load();
                 } catch (IOException ioexception) {
-                    NameReferencingFileConverter.LOGGER.warn("Could not load existing file {}", ipbanlist.b().getName(), ioexception);
+                    NameReferencingFileConverter.LOGGER.warn("Could not load existing file {}", ipbanlist.b().getName()); // CraftBukkit - don't print stacktrace
                 }
             }
 
@@ -186,7 +191,7 @@
                 try {
                     oplist.load();
                 } catch (IOException ioexception) {
-                    NameReferencingFileConverter.LOGGER.warn("Could not load existing file {}", oplist.b().getName(), ioexception);
+                    NameReferencingFileConverter.LOGGER.warn("Could not load existing file {}", oplist.b().getName()); // CraftBukkit - don't print stacktrace
                 }
             }
 
@@ -230,7 +235,7 @@
                 try {
                     whitelist.load();
                 } catch (IOException ioexception) {
-                    NameReferencingFileConverter.LOGGER.warn("Could not load existing file {}", whitelist.b().getName(), ioexception);
+                    NameReferencingFileConverter.LOGGER.warn("Could not load existing file {}", whitelist.b().getName()); // CraftBukkit - don't print stacktrace
                 }
             }
 
@@ -353,6 +358,30 @@
                         File file5 = new File(file, s2 + ".dat");
                         File file6 = new File(file4, s3 + ".dat");
 
+                        // CraftBukkit start - Use old file name to seed lastKnownName
+                        NBTTagCompound root = null;
+
+                        try {
+                            root = NBTCompressedStreamTools.a(new java.io.FileInputStream(file5));
+                        } catch (Exception exception) {
+                            exception.printStackTrace();
+                        }
+
+                        if (root != null) {
+                            if (!root.hasKey("bukkit")) {
+                                root.set("bukkit", new NBTTagCompound());
+                            }
+                            NBTTagCompound data = root.getCompound("bukkit");
+                            data.setString("lastKnownName", s2);
+
+                            try {
+                                NBTCompressedStreamTools.a(root, new java.io.FileOutputStream(file2));
+                            } catch (Exception exception) {
+                                exception.printStackTrace();
+                            }
+                       }
+                        // CraftBukkit end
+
                         NameReferencingFileConverter.a(file4);
                         if (!file5.renameTo(file6)) {
                             throw new NameReferencingFileConverter.FileConversionException("Could not convert file for " + s2);
