diff --git a/changelog.txt b/changelog.txt
index 2dca36203..29caca258 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -1,5 +1,9 @@
 EQEMu Changelog (Started on Sept 24, 2003 15:50)
 -------------------------------------------------------
+== 04/22/2015 ==
+Uleat: Probable fix for 'Debug Assertion Failure' in Client::GarbleMessage() when calling the 'isalpha' macro.
+ref: https://connect.microsoft.com/VisualStudio/feedback/details/932876/calling-isdigit-with-a-signed-char-1-results-in-a-assert-failure-in-debug-compiles
+
 == 03/29/2015 ==
 Secrets: Identified the Target Ring fields for RoF/RoF2.
 Secrets: Added a perl accessor for the last target ring position received from the client. Usage: $client->GetTargetRingX(), $client->GetTargetRingY(), $client->GetTargetRingZ()
diff --git a/zone/client.cpp b/zone/client.cpp
index 677884171..ad1863a05 100644
--- a/zone/client.cpp
+++ b/zone/client.cpp
@@ -7500,7 +7500,7 @@ void Client::GarbleMessage(char *message, uint8 variance)
 		}
 
 		uint8 chance = (uint8)zone->random.Int(0, 115); // variation just over worst possible scrambling
-		if (isalpha(message[i]) && (chance <= variance)) {
+		if (isalpha((unsigned char)message[i]) && (chance <= variance)) {
 			uint8 rand_char = (uint8)zone->random.Int(0,51); // choose a random character from the alpha list
 			message[i] = alpha_list[rand_char];
 		}