Be aware that 64 bit operating systems along with 64 bit MS Access could spell trouble for your code. It will spell trouble for any libraries that you may hav e obtained along the way. There is a nearly total absence in the market of 64 bit versions of libraries. I would warn clients ahead of time if you can. Look through your client list and those that you know have unique libraries for whatever reason, contact them and let them know they will lose that function if they make the upgrade. The idea of 64 bit is wonderful. The reality of it is harsh.