In the Event Viewer I've a lot of errors about "Event ID 6003 winlogon" from
30 January to 28 March (I performed a clean installation on 30 January).
Is it a bug? Do you have these event id 6003 winlogon errors into Event
viewer?

Event ID: 6003 Source: Winlogon and says:
The winlogon notification subscriber <TrustedInstaller> was unavailable to
handle a critical notification event.

And only today I've got a similar error during the logon, i.e. I clicked on
my user, typed my password and Vista shown a dialog box with a similar/same
error, then I retried again an login worked.

Somewhat of a guess but it sounds like some software that is trying to
update itself but is not completely compatible. Probably requires Admin
privs for the update. The obvious culprits would be AV/security software,
anti-spyware, etc. Try running manual updates on these and see if you get
errors.

I had a misbehaving piece of software that activated a UAC message every
time it went to check for updates. Then last week, I get a notice that a new
version is available and everything has been as expected since.

"BillD" <BillD@discussions.microsoft.com> wrote in message
news:B19CC5DB-BEED-4B90-863A-E89AF0FA49C0@microsoft.com...
> In the Event Viewer I've a lot of errors about "Event ID 6003 winlogon"
> from
> 30 January to 28 March (I performed a clean installation on 30 January).
> Is it a bug? Do you have these event id 6003 winlogon errors into Event
> viewer?
>
> Event ID: 6003 Source: Winlogon and says:
> The winlogon notification subscriber <TrustedInstaller> was unavailable to
> handle a critical notification event.
>
> And only today I've got a similar error during the logon, i.e. I clicked
> on
> my user, typed my password and Vista shown a dialog box with a
> similar/same
> error, then I retried again an login worked.