I Installed postgre using the windows installer and later on did a uninstall.
Later when i tried installing again, the installer never allowed me to install with the normal settings of User Postgre and superuser Postgre
It always gave me the error
'User Doesnot exists'.
or Unable to install, Security name Not mapped to the UserID
Windows machine :
Go to your Control Panel -> User Accounts ->Advanced -> Advanced USer Management Advanced USer Management -> Advanced
You would be seeing all the Local Users/Groups
you would find the intial username used while installing Postgre.
You can right click -> delete
or create a New User and make him a normal User group
and then use the same username while postgre install.