Daylight Savings — The Day After


The Issue

Daylight savings is that time of the year when the clocks “move back” one hour (or forward in the Spring). This year we had a client who experienced an interesting problem resulting in a service outage involving daylight savings.

The computer in question, running Windows XP, didn’t jump just 1 hour ahead, but 13 hours ahead. This resulted in noone being able to sign on to the domain on the computer because of the following error message:

“Current time on computer does not match current time on network”

The FixSimply log on to the computer and adjust the time to match the time on the Domain Controller.

Wait, if I can’t log on, how can I change the time? Two methods:

  1. Unplug the network cable and log on. Then you can change the time, plug the network cable back in, and reboot the machine.
  2. Reboot the machine and during the boot screen activate the BIOS.  In there is a “DATETIME” option which will let you reset the clock.

Why it works!

  1. When a user logs onto a computer which is part of a domain, it checks with the domain controller, “the ruler of the domain” to verify the user’s Id and password. However, if the computer cannot find a Domain Controller, the computer will still permit log ons using “stored credentials”. Basically, it remembers the last few people to log on and their password in case the Domain Controller is having issues. By unplugging the network cable, you simulate a “network down” event which allows access the computer.
  2. Signing on to BIOS is controlling the actual clock of the machine directly. Thus, it bypasses most security restrictions (except for a BIOS password). The downside is you have to be at least somewhat comfortable with BIOS. Technicians shouldn’t have a problem, but non-technical staff might be hesitate. Booting to the BIOS may differ from machine to machine, so read up on your make and model of machine to find out how to boots to bios for you.

Recommendation

I recommend trying Option 1 first. If that doesn’t work, possibly because the user doesn’t have permissions to change time, then revert to Option 2.

 

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