After installing binary for WSS SP1 and MOSS SP1 and running Configuration Wizard I’ve received Upgrade failed message on step 6 of 9. Event log had shown Eventid 104 and 100. Inspection of Services had shown that the Timer service has been stopped after trying to restart it "logon failure" was thrown, resetting the identity of this service back to farm admin account has resulted in the successful start of this service. I rerun Configuration Wizard now step 8 of 9 "fails to start SPSearch Service Instance, start it manually" and it followed by the same failure to upgrade message.
Further inspecting logs revealed that search could not start due to logon failure as well.
What solved it all was resetting WSS Search to farm admin account explicitly and rerunning Config Wizard.
I’m not exactly sure why it had to be done so, this was a development environment the was in fairly healthy state and all services had been running under the same farm admin account. The logon failure messages did not make much since since all services were running fine before the upgrade.
But it worked.
Time to upgrade the production environment, oh.. almost forgot … Infrastructure Updates time