I am still not clear how you able to pass customer authentication.
This does NOT happen on your site now. I tried.

1. Are you sure you do not click (or clicked before) "act on behalf" in admin?
2. What browser do your customer use?
3. Did you modify any code at that time?

1. No
2. Can't say unfortunately
3. No code alterations but there have been two extensions installed - Wishlist and Abandoned Orders, three language packs and Flexi-promotions.

We have just done a test here.

Downstairs on computer1 the browser was logged into admin and had added a couple of items to the Cart.
Upstairs on computer2 I navigated to abantecart and clicked on the 'cart' icon without logging in. The cart details from the session on the computer1 was displayed and to all extents and purposes the sessions on comuter2 was logged in as if it was the sessions on computer1.

The only reasons I can think of for this to happen are that both computers operate on the IP external IP address.
Or computer2 has cache from when it was last legitimately logged in as admin - which would have been several weeks ago.In any case neither of those explain why customers in one country can see details of a customer logged in in another.

Hi, No, I am not getting the problem in the demo but checked again and am still getting the same with my site (using different browsers). I feel sure it is a setting that one of us here must have changed then forgot about. Thanks for the attention. I will PM the URL and log in details.

Hi, The first day we went live with AbanteCart cart we discovered that when someone was logged in the next customer to click the account tab went straight to the account page of the customer already logged in...giving access to personal details ect. We discovered this when we were setting up the store and testing but thought it was just on computers on our network, until a customer alerted us that it was not just out network......we took AbanteCart cart down quickly. I had installed some extensions so I disabled these and tested again with the same result. Help please!

Hi, I am really impressed with this cart so far. I am in the process of migrating from cube cart. The main reason is that customers who have registered with the site can not then checkout as a guest using the same e mail address. They get an error message "that e mail is already being used". We believe their password is then disrupted so they can not log in. Cube cart have not been able to do anything about this and we are loosing business. I am now concerned that we may have the same problem with AbanteCart cart. My basic question is, if a registered customer wants to checkout as guest using the same e mail, can they do so? I am stopping the work on migration at the moment hoping the answer to this is yes and we can go ahead.