There was this situation where the end user was trying to configure automated builds in Rational Team Concert (RTC) 4.0.5, but was unable to get it to work.
They had scheduled the builds to run at a specific time everyday but it never used to run. Here is the screenshot of their scheduler configuration.
However, manual builds used to work just fine after configuring the Build Engine to run as Windows scheduled task on their RTC build server.
Build scheduled task used the same Windows account which is the owner of Build workspace and they couldn't identify what was wrong.
Essentially, it's not suffice just to mention 'Everyday' along with the build time. It's required to select all Build days as well, as shown in the screenshot here.
Open the build definition in question from Eclipse client.
Go to 'schedule' tab; Here one should select the 'Build Time' and 'Select All' for the build days as shown in the screenshot.
Then save. Now the scheduled build works just fine and this was the missing thing here.