diff --git a/doomsday/libdeng2/include/de/data/stringpool.h b/doomsday/libdeng2/include/de/data/stringpool.h
index ef97204dc7..42ea208492 100644
--- a/doomsday/libdeng2/include/de/data/stringpool.h
+++ b/doomsday/libdeng2/include/de/data/stringpool.h
@@ -61,6 +61,9 @@ namespace de
         /// String identifier was invalid. @ingroup errors
         DENG2_ERROR(InvalidIdError);
 
+        /// The pool does not have any available identifiers. @ingroup errors
+        DENG2_ERROR(FullError);
+
         /// String identifier. Each string is assigned its own Id. Because this is
         /// 32-bit, there can be approximately 4.2 billion unique strings in the pool.
         typedef duint32 Id;
diff --git a/doomsday/libdeng2/src/data/stringpool.cpp b/doomsday/libdeng2/src/data/stringpool.cpp
index ce94a96c3a..db2fdb29b2 100644
--- a/doomsday/libdeng2/src/data/stringpool.cpp
+++ b/doomsday/libdeng2/src/data/stringpool.cpp
@@ -36,6 +36,8 @@
 #define EXPORT_ID(i)    (duint32(i) + 1)
 #define IMPORT_ID(i)    (Id((i) - 1))
 
+#define MAXIMUM_VALID_ID (0xffffffff - 1)
+
 namespace de {
 
 static String const nullString = "(nullptr)";
@@ -233,6 +235,12 @@ struct StringPool::Instance
         }
         else
         {
+            if(idMap.size() >= MAXIMUM_VALID_ID)
+            {
+                throw StringPool::FullError("StringPool::assignUniqueId",
+                                            "Out of valid 32-bit identifiers");
+            }
+
             // Expand the idMap.
             idx = idMap.size();
             idMap.push_back(str); // O(1) (amortized)