I installed 4.6.2 and readded the "Network Service" permissions (im on win2k3) and browsed tp the upgrade page which prompted me for a password. I clicked cancel and got the following...

00:00:00.265 - Upgrading to Version: 4.6.2
00:00:00.375 -   Executing Script: 04.06.01.SqlDataProvider Success
00:00:00.968 -   Executing Script: 04.06.02.SqlDataProvider Success
00:00:00.984 - Performing General Upgrades
00:00:01.968 - Installing Module File Adsense_01.00.01_Install:  Success
00:00:03.937 - Installing Module File HTML_04.05.00_Install:  Success
00:00:05.281 - Installing Module File HTML_04.06.01_Install:  Success
00:00:06.578 - Installing Module File Links_03.03.07_Install:  Success
00:00:07.656 - Installing Package File LiveID_01.00.00_Install:

Server Error "/"

Value cannot be null
Parameter name: format
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: format

I do not understand why IIS is prompting for a password when my DNN dir has just been given "Full Access" priviledges to the "Network Service" user.

Can anyone help me out?

Ahh ok i fixed the issue.

It seems when "Integrated Windows Security" is enabled it prompts for user/pass i disabled that option and all is well! :)