diff --git a/core/sys/info/platform_windows.odin b/core/sys/info/platform_windows.odin
index e7d3baa83..585269774 100644
--- a/core/sys/info/platform_windows.odin
+++ b/core/sys/info/platform_windows.odin
@@ -366,7 +366,7 @@ read_reg_string :: proc "contextless" (hkey: sys.HKEY, subkey, val: cstring16, r
 		return
 	}
 
-	utf16.decode_to_utf8(res_buf[:result_size], buf_utf16[:])
+	utf16.decode_to_utf8(res_buf[:], buf_utf16[:result_size / size_of(u16)])
 	res = string(cstring(&res_buf[0]))
 	return res, true
 }