Why can i not change my main Email address on this site ?

There's an edit link next to your email addresses on https://launchpad.net/~.

No this does not work. I used the same page you have advised beforehand and cannot delete my original Email address and set a new one. Actually i have done this three times.!

Delete the word beforehand in the previous sentence.

What doesn't work, and how doesn't it work?

If you're trying to delete the old address first, that isn't allowed. You can't delete your only email address -- you have to add the replacement one, then set it as your preferred address, then delete the old one.

I just get no entry signs when i press the remove Email button.

You get an error message when you click the Remove button. You still haven't added a second address.

I have tried that AFTER i had added a new Email address and got red no entry signs. How do you set it as your preferred Email address ? that option is not clearly shown !

You only have a single confirmed email address. You haven't added a second one, or haven't clicked the confirmation link in the email that it asked you to open to validate that you own the address.

In the latter case, you'll see one address under "These addresses are confirmed as being yours:" and the new one under "These addresses may also be yours:". You need to confirm that an address is yours before you can use it as your preferred address.

I think this one is a famous bug one that goes around in circles !

There's no bug here. You just haven't added a second address, so you can't change your preferred address, so you can't remove the old preferred address.

If you can't add a second address, or can't change the preferred address once you've added a second address, or can't delete the old preferred address once you've done the switch, describe precisely the steps you took and the exact text of any error messages your receive.

Regarding my second address i was not told or informed to confirm it in the first place after i clicked the button. Why should i have to validate my second address in launchpad anyway as i'm a logged on user ? i have not yet seen any dialog relating to what you have mentioned about confirmation but will take another look.

You have a confirmation email in the inbox of the address that you added. Click the link in that email.

Launchpad needs to verify that you own an address before you can use it. Letting people add arbitrary addresses makes impersonation of innocent users easy, and gets people locked out of their accounts when they can't reset their passwords.

Keeps on logging me out so i have to log back in then it starts all over again in a programmers loop thing -- press remove (original) account and get error 1 then red no entry signs.?? I am not offered the option of preferred address. ??

I will not be around for a couple of days but will be in contact. I do find this thing very strange and the fact the preferred address thing is not showing !

You still haven't confirmed your second address. You need to do that BEFORE you can change and then remove your current preferred address.

 0) If you haven't already done so, enter the new address under "Add a new address:" and click "Add".
 1) Click the "Confirm" button on https://launchpad.net/~/+editemails.
 2) Check the inbox for that address.
 3) Click the link in the confirmation email from Launchpad.
 4) Click the button on that page to confirm the address.
 5) Go back to https://launchpad.net/~/+editemails, select the new address, and click "Set as Contact Address".
 6) Select the old address and click "Remove".

In that order.