diff --git a/xml/System.Collections.Immutable/ImmutableDictionary.xml b/xml/System.Collections.Immutable/ImmutableDictionary.xml
index 74c6d61dd39..7de46261b7c 100644
--- a/xml/System.Collections.Immutable/ImmutableDictionary.xml
+++ b/xml/System.Collections.Immutable/ImmutableDictionary.xml
@@ -935,6 +935,7 @@
Enumerates a sequence of key/value pairs and produces an immutable dictionary of its contents.
An immutable dictionary that contains the key/value pairs in the specified sequence.
To be added.
+ An element with the same key but a different value already exists in the dictionary.
@@ -1049,6 +1050,7 @@
Enumerates a sequence of key/value pairs and produces an immutable dictionary of its contents by using the specified key comparer.
An immutable dictionary that contains the key/value pairs in the specified sequence.
To be added.
+ An element with the same key but a different value already exists in the dictionary.
@@ -1126,6 +1128,7 @@
Enumerates a sequence of key/value pairs and produces an immutable dictionary of its contents by using the specified key and value comparers.
An immutable dictionary that contains the key/value pairs in the specified sequence.
To be added.
+ An element with the same key but a different value already exists in the dictionary.
@@ -1179,6 +1182,7 @@
Constructs an immutable dictionary from an existing collection of elements, applying a transformation function to the source keys.
The immutable dictionary that contains elements from , with keys transformed by applying .
To be added.
+ An element with the same key but a different value already exists in the dictionary.
@@ -1242,6 +1246,7 @@
Constructs an immutable dictionary based on some transformation of a sequence.
The immutable dictionary that contains elements from , with keys transformed by applying .
To be added.
+ An element with the same key but a different value already exists in the dictionary.
@@ -1306,6 +1311,7 @@
Enumerates and transforms a sequence, and produces an immutable dictionary of its contents.
An immutable dictionary that contains the items in the specified sequence.
To be added.
+ An element with the same key but a different value already exists in the dictionary.
@@ -1380,6 +1386,7 @@
Enumerates and transforms a sequence, and produces an immutable dictionary of its contents by using the specified key comparer.
An immutable dictionary that contains the items in the specified sequence.
To be added.
+ An element with the same key but a different value already exists in the dictionary.
@@ -1463,6 +1470,7 @@
Enumerates and transforms a sequence, and produces an immutable dictionary of its contents by using the specified key and value comparers.
An immutable dictionary that contains the items in the specified sequence.
To be added.
+ An element with the same key but a different value already exists in the dictionary.
diff --git a/xml/System.Collections.Immutable/ImmutableDictionary`2+Builder.xml b/xml/System.Collections.Immutable/ImmutableDictionary`2+Builder.xml
index 44a410dd8ad..537183bca6d 100644
--- a/xml/System.Collections.Immutable/ImmutableDictionary`2+Builder.xml
+++ b/xml/System.Collections.Immutable/ImmutableDictionary`2+Builder.xml
@@ -188,7 +188,7 @@
To be added.
is null.
- An element with the same key already exists in the dictionary.
+ An element with the same key but a different value already exists in the dictionary.
The dictionary is read-only.
diff --git a/xml/System.Collections.Immutable/ImmutableDictionary`2.xml b/xml/System.Collections.Immutable/ImmutableDictionary`2.xml
index 16f6906f140..8d3a98b4dc5 100644
--- a/xml/System.Collections.Immutable/ImmutableDictionary`2.xml
+++ b/xml/System.Collections.Immutable/ImmutableDictionary`2.xml
@@ -1051,7 +1051,7 @@ This example shows how to create a new immutable dictionary by adding and removi
To be added.
is .
- An element with the same key already exists in the .
+ An element with the same key but a different value already exists in the .
The is read-only.