diff --git a/reactos/include/ddk/wdm.h b/reactos/include/ddk/wdm.h
index 3a523235742..af239bbb4c3 100644
--- a/reactos/include/ddk/wdm.h
+++ b/reactos/include/ddk/wdm.h
@@ -9459,7 +9459,7 @@ RtlCheckBit(
 
 #define ASSERTMSG(msg, exp) \
   (VOID)((!(exp)) ? \
-    RtlAssert( (PVOID)#exp, (PVOID)__FILE__, __LINE__, msg ), FALSE : TRUE)
+    RtlAssert( (PVOID)#exp, (PVOID)__FILE__, __LINE__, (PCHAR)msg ), FALSE : TRUE)
 
 #define RTL_SOFT_ASSERT(exp) \
   (VOID)((!(exp)) ? \
diff --git a/reactos/include/xdk/rtlfuncs.h b/reactos/include/xdk/rtlfuncs.h
index a5302dcea9f..ee7742c2f94 100644
--- a/reactos/include/xdk/rtlfuncs.h
+++ b/reactos/include/xdk/rtlfuncs.h
@@ -1858,7 +1858,7 @@ RtlCheckBit(
 
 #define ASSERTMSG(msg, exp) \
   (VOID)((!(exp)) ? \
-    RtlAssert( (PVOID)#exp, (PVOID)__FILE__, __LINE__, msg ), FALSE : TRUE)
+    RtlAssert( (PVOID)#exp, (PVOID)__FILE__, __LINE__, (PCHAR)msg ), FALSE : TRUE)
 
 #define RTL_SOFT_ASSERT(exp) \
   (VOID)((!(exp)) ? \