diff --git a/runelite-client/src/main/java/net/runelite/client/plugins/kourendlibrary/Library.java b/runelite-client/src/main/java/net/runelite/client/plugins/kourendlibrary/Library.java
index 02618031db..5af160da87 100644
--- a/runelite-client/src/main/java/net/runelite/client/plugins/kourendlibrary/Library.java
+++ b/runelite-client/src/main/java/net/runelite/client/plugins/kourendlibrary/Library.java
@@ -131,7 +131,7 @@ class Library
 		else if (state != SolvedState.NO_DATA)
 		{
 			// We know all of the possible things in this shelf.
-			if (book != null)
+			if (book != null || bookcase.getPossibleBooks().stream().noneMatch(Book::isDarkManuscript))
 			{
 				// Check to see if our guess is wrong
 				if (!bookcase.getPossibleBooks().contains(book))