diff --git a/src/libWiiPy/nand/emunand.py b/src/libWiiPy/nand/emunand.py
index ed880bc..bffa9d2 100644
--- a/src/libWiiPy/nand/emunand.py
+++ b/src/libWiiPy/nand/emunand.py
@@ -128,6 +128,10 @@ class EmuNAND:
         uid_sys = _UidSys()
         if not uid_sys_path.exists():
             uid_sys.create()
+        else:
+            uid_sys.load(uid_sys_path.read_bytes())
+        uid_sys.add(title.tmd.title_id)
+        uid_sys_path.write_bytes(uid_sys.dump())
 
     def uninstall_title(self, tid: str) -> None:
         """
diff --git a/src/libWiiPy/nand/sys.py b/src/libWiiPy/nand/sys.py
index 54b2859..9b1440d 100644
--- a/src/libWiiPy/nand/sys.py
+++ b/src/libWiiPy/nand/sys.py
@@ -77,7 +77,8 @@ class UidSys:
 
     def add(self, title_id: str | bytes) -> int:
         """
-        Adds a new Title ID to the uid.sys file and returns the UID assigned to that title.
+        Adds a new Title ID to the uid.sys file and returns the UID assigned to that title. The new entry will only
+        be added if the provided Title ID doesn't already have an assigned UID.
 
         Parameters
         ----------
@@ -106,6 +107,11 @@ class UidSys:
             title_id_converted = title_id
         else:
             raise TypeError("Title ID type is not valid! It must be either type str or bytes.")
+        # Ensure this TID hasn't already been assigned a UID. If it has, just exit early and return the UID.
+        if self.uid_entries.count != 0:
+            for entry in self.uid_entries:
+                if entry.title_id == title_id_converted:
+                    return entry.uid
         # Generate the new UID by incrementing the current highest UID by 1.
         try:
             new_uid = self.uid_entries[-1].uid + 1