OK, I have done my first V3 local install. (gave up on using composer for now)
Instantly I have some problems.
apache crashes on loading http://localhost/mysite/home/successfullyinstalled?flush=1
I try over and over but no.
If I go to admin, I don't know my password (was I supposed to get an email?)
If I click 'I ve lost my password', enter my email I used, and click to continue.. a large error message is flashed, and then hidden again by the page..
using the stop but very fast I can get it.
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[Warning] mail() [function.mail]: Failed to connect to mailserver at "localhost" port 25, verify your "SMTP" and "smtp_port" setting in php.ini or use ini_set()
POST /vhost/DusXproductionsV3/Security/LostPasswordForm

Line 167 in C:\xampp\htdocs\vhost\mysite\framework\email\Mailer.php
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What do I need to do to fix it and be able to login locally?

Hi DsX,

Do you have a maildaemon running on your local machine? If it's not properly configured, the SS3 installation will be unable to mail your password. It shouldn't matter though since you'll be able to change the password directly, in the database.

Do other systems cause your Apache instance to crash or is it just SS3?

Any more details you can give us could be helpful in providing more context so we can give you some better advice.

Thanks.

BTW you may also want to try configuring a username and password in mysite/_config.php

http://doc.silverstripe.org/framework/en/topics/environment-management

/* Configure a default username and password to access the CMS on all sites in this environment. */
define('SS_DEFAULT_ADMIN_USERNAME', 'username');
define('SS_DEFAULT_ADMIN_PASSWORD', 'password');