diff --git a/src/lib/support/StringBuilder.cpp b/src/lib/support/StringBuilder.cpp
index be0a0197471b6e..8143f95237d4c2 100644
--- a/src/lib/support/StringBuilder.cpp
+++ b/src/lib/support/StringBuilder.cpp
@@ -36,7 +36,7 @@ StringBuilderBase & StringBuilderBase::AddFormat(const char * format, ...)
     // on invalid formats, printf-style methods return negative numbers
     if (needed > 0)
     {
-        mWriter.Skip(needed);
+        mWriter.Skip(static_cast<size_t>(needed));
     }
 
     va_end(args);