diff --git a/CMakeLists.txt b/CMakeLists.txt
index 88dd1ee..2580ec5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -436,7 +436,8 @@ if(SIZEOF_LONG_LONG EQUAL 8)
   set(CURL_FORMAT_CURL_OFF_TU "llu")
   set(CURL_FORMAT_OFF_T "%lld")
   set(CURL_SUFFIX_CURL_OFF_T LL)
-  set(CURL_SUFFIX_CURL_OFF_TU LLU)
+  # NB: MS Visual Studio x64 Compiler does not recognize "LLU" as valid suffix.
+  set(CURL_SUFFIX_CURL_OFF_TU ULL)
 endif(SIZEOF_LONG_LONG EQUAL 8)
 
 if(NOT CURL_TYPEOF_CURL_OFF_T)