Dcom component won't retain its credentials

Question

I've recently moved a 3rd party very old Web app from a Win. 2003 server to a Win 2008 R2 server.

The app uses a DCOM component (Microsoft Word Document) which runs under a particular user account.

When I enter credentials for the component it all works fine for a few hours then wallop, it fails.

If I reenter the password in the component credentials all is good again until it blows up a few hours later.

What could be preventing this component from retainng its credentials indefinately?

I'm thinking the antivirus (McAfee) or maybe a Group Policy could be preventing permanent changes but that wouldn't really make sense as if one is going to prevent some change why allow it at all. I'm really stumped and so is the software vendor!

Answer 1

It turns out the component was running under a domain account. When using domain accounts the account must have the Logon as a Service privilege set in the local or group policy. Our GP was overriding many local policies. Granting this privilege to the account in the GP and bingo, problem solved. Not much out there on the web about this problem as it only occurs rarely (I expect few DCOM components use do domain accounts - probably for good reason!).