Where there are multiple versions of windows installed, the Boot Menu is displayed for 30 seconds, giving time to the user to choose the OS, after which the computer boots into the default OS. You can also customize the time-out value, either through the Boot.ini file or through bcdedit. In Windows, you can use BCDEdit, to change the default boot menu time-out value.
In earlier versions like Windows XP, the Boot Menu Timeout was from 0 to 9999 seconds. A value of ‘-1‘ was also permitted, meaning that the machine would not boot unless and until the User made a choice.
Starting with Windows Vista, using msconfig, users can enter a value between 3 and 999 seconds only. The -1 value has been removed in Windows Vista and later.
Raymond Chen, a developer on Microsoft’s Windows Shell team, while answering the following question, has pointed out a way where, one can actually go to maximum of 11,059,200 seconds for the Boot Menu Timeout:
We have a number of kiosk machines that are networked wirelessly. Each machine is configured with automatic logon so that things return to normal after power is restored after an outage. The problem is that the wireless switch takes a long time to recover from a power failure, so when the kiosk machines try to log on, they can’t. We have to go around to all the machines and manually log them on after waiting a few minutes for the switch to get itself back up. Is there a way we can delay the automatic logon or convince automatic logon to pause and retry?
To do it, launch a command prompt with elevated privileges and enter the following:
bcdedit /timeout 11000000
This will bypass the limitations of msconfig and set the Boot Menu Timeout to 11 million seconds or around 128 days or around 4 months.