Hi Fred,
Normally if you tell an Agent to use a different login object (with a different Domain\username) then that new Domain\username needs to also exist as an Account to where the Agent is installed at.
The error you are getting
'U02001007 User 'domain\acct' is unknown or an invalid password has been provided.'
I can reproduce it easily on my system if I go to my Window machine... and remove the AD user account, from the window machine (in which I had used/define in my login Object)...
What you are describing is exactly how my system is currently running (over90% is run by let call it LOGIN.A (which is set to a generic IT user+that also happen to be the account that started the Agent) and when I want to run something as someone else. I change it to a different login object (that has a different user credential) but I have to make sure that credential I used in the login ALSO must have an account ON the window machine itself.
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I haven't seen a confirmation on this or maybe I missed something from all the comment/discussion above so i'll ask again... this Login.ACCT2... Since you mention that this is an active directory users.
Does that Account (Domanin\SVCacct) exist as an Active Directory users account on the Window machine itself (where the Window agent you are using was installed)? In the sense that if you go to that window machine, you can log in with that credential 'new' domain\username?