Orders not showing up

This has happened several times. I'll receive a Notification of Payment Received from Paypal but no actual order is generated by the site. There will be no order email telling me what was purchased nor will there be any record of the order in the Admin, although it will show that the customer did register an account with the site.
I had one customer that had this happen several times then suddenly his latest order completed as normal. When asked, he said he did nothing different from previous orders. I have had several orders from other customers not appear since then so it's not just him.
It gets very frustrating and looks unprofessional to email the customer and ask what they ordered. Has anyone else had this problem and possibly found a solution?

:dontgetit

Yes - lots have had that problem.

It's usually a result of having out-of-date PayPal code.
Are you using Zen Cart v1.3.7 without the patches?: http://www.zen-cart.com/forum/showthread.php?t=56216

Or else it's a result of unsuccessful communications from PayPal's server to yours:
Here is a guide to troubleshoot that situation: http://www.zen-cart.com/wiki/index.php/PayPal

DrByte:

Yes - lots have had that problem.

It's usually a result of having out-of-date PayPal code.
Are you using Zen Cart v1.3.7 without the patches?: http://www.zen-cart.com/forum/showthread.php?t=56216

Or else it's a result of unsuccessful communications from PayPal's server to yours:
Here is a guide to troubleshoot that situation: http://www.zen-cart.com/wiki/index.php/PayPal

Thanks for the response. I'm using 1.3.7.1. It was installed for me so I'm not sure if patches were installed or not. I'll contact the person who set it up and see.

Checked with my designer and according to him, all patches are up-to-date.

A customer helped me identify the problem. It seems that if you wait for Paypal to redirect you to the website after the payment is completed, the order will complete. If for some reason the customer closes the browser window or goes somewhere else after the payment is made but before the redirect, the order doesn't get generated.
How can I get around this?

theehman:

A customer helped me identify the problem. It seems that if you wait for Paypal to redirect you to the website after the payment is completed, the order will complete. If for some reason the customer closes the browser window or goes somewhere else after the payment is made but before the redirect, the order doesn't get generated.
How can I get around this?
Your options:
a) do not accept payments from people without PayPal accounts if you're going to use the IPN module
or
b) lobby PayPal to change their methods so that they no longer encourage folks to create PayPal accounts (but, since it's in PayPal's best interest to get new accounts, this will likely not be an option)
or
c) don't use the IPN module ... use Express Checkout instead
or
d) use a regular credit card merchant account instead of PayPal