When installing Sitecore 9 (using SIF) you execute a powershell script called XP0-SingleDeveloper.ps1
(at least for installing a Single On Premises instance). In this file you should find a line that looks like this:
$SitecoreAdminPassword = "SIF-Default"
That line determines the password used for the admin
user. Change this to whatever you want, and after the installation is completed you can log on as admin using that password (you can even set the password to "b" if you want to).
As per the installation documentation:
[...] edit the
XP0-SingleDeveloper.ps1
script and update each line with the settings that are appropriate for your environment. One of the settings that you must edit isSitecoreAdminPassword
.
If you do not specify the Sitecore administrator password in the script and leave the example value "SIF-Default" unchanged, a random password is generated for you. This password is written to the
XP0-SingleDeveloper.log
file – search for Sitecore Admin Password – and displayed when thesitecore-xp0.json
file has been processed