diff --git a/src/OSInfo.cpp b/src/OSInfo.cpp
index bdad3aab8..b73c719f7 100644
--- a/src/OSInfo.cpp
+++ b/src/OSInfo.cpp
@@ -34,7 +34,9 @@ static QString regString(wchar_t *string, int size) {
 	// that the NUL is not included in the returned
 	// string.
 	const size_t adjustedSize = wcsnlen(string, static_cast<size_t>(size));
-	return QString::fromWCharArray(string, adjustedSize);
+	// The return value of wcsnlen is <= size which is
+	// an int, so casting adjustedSize to int is safe.
+	return QString::fromWCharArray(string, static_cast<int>(adjustedSize));
 }
 
 /// Query for a Windows 10-style displayable version.