Sorry for the necromancy, but this additional account being created on my windows machine was really bugging me and I thought I'd post my findings here if anybody else is looking.

*Disclaimer: I'm a n00b on Odoo, so my methods are most certainly not best practice and may break your installation. Also I'm just running an experimental localhost and have no idea how this will effect your server environments.

I deleted this profile as an experiment and this is what I've found:

From what I can gather this account is used to start the PostgreSQL server service. If you delete it the Odoo server will return the "Internal Server Error" and you will not be able to access your database (not even from PgAdmin)

To fix this (In Windows), simply run 'services.msc', and under the PostgreSQL_for_Odoo service select:

You will notice the service is not running and attempting to start it will result in an authentication error.

rightclick>>properties>>Log On>> & select 'Local System Account' (or alternatively you can start the service with a different user accounts credentials)

This gets it running again, but I'm pretty certain it must an affect on some of the add ons.

For now I'm just running task management & Projects and found that the editing description boxes on tasks required me to start using an etherpad server in the Business Settings (This worked OOTB before deleting this account so it seems related)

My fix for that was to just install the latest windows version of etherpad (http://etherpad.org/) into my %PROGRAMDATA%\Odoo Folder.

The start.bat runs the server (I needed to edit the default config in settings.json from IP 0.0.0.0 to localhost) and sets up on http://localhost:9001, but the command window has to be running the whole time. To get around this I created a file with the following line of text:

CreateObject("Wscript.Shell").Run """" & WScript.Arguments(0) & """", 0, False

and saved it as %PROGRAMDATA%\Odoo\etherpad\Invisible.vbs

Then i created a file with the following text file:

wscript.exe "%PROGRAMDATA%\Odoo\etherpad\Invisible.vbs" "%PROGRAMDATA%\Odoo\etherpad\start.bat"

and saved it as %PROGRAMDATA%\Odoo\etherpad\Start Invisible.bat

After that I just created a shortcut to 'Start Invisible.bat' and added it to startup apps (win+R, type in "shell:startup")

So far so good. I'm sure there'll be hiccups down the line, but personally it beats the pants off having some random user account with a generic password posing a security risk on my machine.