diff --git a/core/src/com/riiablo/io/InvalidFormat.java b/core/src/com/riiablo/io/InvalidFormat.java
new file mode 100644
index 00000000..0f38d4bc
--- /dev/null
+++ b/core/src/com/riiablo/io/InvalidFormat.java
@@ -0,0 +1,28 @@
+package com.riiablo.io;
+
+public class InvalidFormat extends RuntimeException {
+  public final long offset;
+
+  public InvalidFormat(ByteInput in, String message) {
+    this(in, message, null);
+  }
+
+  public InvalidFormat(ByteInput in, Throwable cause) {
+    this(in, "Invalid format", cause);
+  }
+
+  public InvalidFormat(ByteInput in, String message, Throwable cause) {
+    super(message + " @0x" + Integer.toHexString(in.bytesRead()), cause);
+    this.offset = in.bytesRead();
+  }
+
+  @Deprecated
+  public InvalidFormat(String message) {
+    super(message, null);
+    this.offset = 0L;
+  }
+
+  public long offset() {
+    return offset;
+  }
+}
diff --git a/core/src/com/riiablo/item/ItemSerializer.java b/core/src/com/riiablo/item/ItemSerializer.java
index 5065b3c8..40f8668f 100644
--- a/core/src/com/riiablo/item/ItemSerializer.java
+++ b/core/src/com/riiablo/item/ItemSerializer.java
@@ -8,9 +8,9 @@ import com.badlogic.gdx.utils.Array;
 import com.riiablo.Riiablo;
 import com.riiablo.codec.excel.Gems;
 import com.riiablo.codec.util.BitStream;
+import com.riiablo.io.InvalidFormat;
 import com.riiablo.log.Log;
 import com.riiablo.log.LogManager;
-import com.riiablo.save.InvalidFormat;
 import com.riiablo.util.DebugUtils;
 
 public class ItemSerializer {