Support

First things first, DO NOT SHOUT WHEN ASKING FOR SUPPORT. JUST LIKE IN REAL LIFE, WHEN YOU SHOUT AT THE PERSON WHO'S TRYING TO HELP YOU, THE ONLY THING YOU ACHIEVE IS ENERVATING SAID PERSON AND MAKING HIM LESS WILLING TO PUT EFFORT INTO HELPING YOU. See how all caps have a detrimental effect in communication?

Second thing, as very clearly and very prominently stated in our release announcement and download page:

Alpha (testing) releases have undergone minimal testing and are not suitable for use on production sites. We strongly advise you to install on a development site first and report any bugs you may find. Bugs not reported can not be fixed. Thank you in advance for your feedback.

Apparently you installed it on a live site against our advice. One more reason not to shout at me.

Now, I have no idea what "I can no longer log in" means. There are at least 5 different issues, of which only one may be related to Akeeba Backup. I mean, do you see the login page? Does it throw an error about a wrong username/password? Does it simply reload without logging you in? Does it log you in but all you get is a blank page or a page reading 500 Internal Server Error? Does it log you in and the menu is deactivated and nothing displays? You see, what you said can mean many different things. Furthermore, you forgot to give me the critical information of PHP version, so I am basically making a wild guess and will try helping you with the problem I guess you have, which is not necessarily the problem you do have.

All of the following steps are mandatory. Start by clearing your browser's cache. Then clear its cookies. Quit the browser (close all windows on Windows or Linux; if you're on a Mac use CMD-Q). Restart the browser and retry logging in. If you still can't log in at all, please provide me with the PHP version and explain what is going on so that I don't have to guess and actually be able to help you.

If after doing the above you get a blank page when logging in, use your FTP programme to rename the administrator/modules/mod_akadmin/akadmin.php to akadmin.php.bak and reload the page. It should now log you in. Re-download Akeeba Backup 3.5.a1 and re-install it.

I have been able to replicate this issue. Actually, it is not caused by Akeeba Backup, but by a partial upgrade. When I tried installing the package again on top of the (paritally) installed version it worked just fine. Can you please confirm that solution?

If this doesn't work, please tell me which version of PHP you are using and the previously installed version of Akeeba Backup so that I can try to replicate the issue you have and solve it.

Thank you in advance!!

Thank you for your feedback! That's the configuration of one of my test servers, so I can rule out the Joomla!, PHP and MySQL version having anything to do with it. This pretty much narrows down this problem to a known issue with Joomla!, intermittently not copying some files when upgrading extensions. For what is worth, installing the same version, the same extension package a second time makes everything work. My only problem is that I can't replicate this issue reliably on a local server so that I can debug it and figure out why Joomla! does that :(