Windows Clock keeps jumping back 8 hours

[Jorpho]

The subject line says it all. For some reason, on occasion, my computer's clock in Windows 7 x64 will jump back exactly eight hours, though no apparent intervention on my part.

I've already tried some of the obvious things, like disabling Internet time synchronization, running a system scan with Malwarebytes, and looking for any scheduled tasks. Nothing has jumped out. The CMOS battery doesn't seem to be dying, and even if it was, the clock wouldn't be consistently losing eight hours. My time zone is UTC -5.

I think the only way I will ever get to the bottom of this is if I ever manage to catch it in the act, but I thought I'd ask if there's any other explanation that I should be aware of.

[ElWanderer]

Does this happen on start-up or during normal running, and do you dual-boot? I have seen weirdness occur where you have two different operating systems (Win XP and Linux in my case) that set/read from the hardware clock differently on exit/start-up. With my PC, the time would be an hour out when I rebooted and switched to the other operating system - something to do with the way British Summer Time was handled. I don't know how that could explain an 8 hour difference, mind.

[Jorpho]

A good thought; I remember seeing something like that on other systems too. But this appears to happen during normal running, and I do not dual boot.

[ElWanderer]

Well, it was worth a (long) shot.

If it's always 8 hours, that does sound more likely to be a software issue than hardware related. Beyond that, I have no idea I'm afraid.

[EdgarJPublius]

Go to the clock settings some time when the clock is reading normal time (right-click on the clock, go to "Adjust date/time")

One the first tab ('Date and Time') Does it show the correct time zone?
On the 'Additional Clocks' tab, are any additional clocks set to show? What time zone are the additional clocks set to?
On the 'Internet Time' tab, Is the computer set to automatically synchronize with an internet time server? Which time server?
Push the 'Change settings...' button and then push 'update now'. Does the clock change what time it shows?

Repeat the above some time when the clock is showing the wrong time and note any differences in settings/behavior.

Possibly try changing which internet time server you synchronize with.

[Jorpho]

The time zone is always set correctly, there are no additional clocks set to show, and as per the OP, the clock jumps back regardless of whether Internet Time is enabled.

[EdgarJPublius]

Have you tried forcing a synchronization when the clock is correct, or when the clock is incorrect? That could definitively rule out any time server shenanigans, such as internet time being enabled when it says it isn't.

[Jorpho]

Yep, forcing a synchronization when the clock is incorrect makes it correct again.

I don't suppose there would be any way to trap any application that tries to set the time, is there?

[freakish777]

Do you sync with any Source Code/Version Control software?

I've run into issues before where some type of version control software needs both the server and the local box to have the same system time (in my case I got error messages where I couldn't check in/check out files, and it was because there was a date mismatch).

Also, try getting the latest updates from Microsoft for Windows. Very unlikely to fix anything, but you may as well.

I don't suppose there would be any way to trap any application that tries to set the time, is there?

Not sure about trapping, but it might show up in Control Panel -> Admin Tools -> Event Viewer -> Windows Log -> System? Maybe use clock as your search term, or set up logging to log when it happens and by what process?

[Jorpho]

Do you sync with any Source Code/Version Control software?

Nope.

Also, try getting the latest updates from Microsoft for Windows. Very unlikely to fix anything, but you may as well.

That is also fully up to date.

Not sure about trapping, but it might show up in Control Panel -> Admin Tools -> Event Viewer -> Windows Log -> System? Maybe use clock as your search term, or set up logging to log when it happens and by what process?

A good idea, and that's one of the places I looked; unfortunately, changing the system time does not count as a loggable event, nor is there any event that looks like it would correspond.

At any rate, the clock has been quite stable for the past couple of days, though I can't think of anything I might have changed that may have been responsible. (Also, the last time I saw the clock change, it only skipped back by four hours for some reason.)

[freakish777]

After a quick search, http://technet.microsoft.com/en-us/libr ... 10%29.aspx looked promising, but a quick test showed that it the command line argument ( w32tm /debug /enable /file:<path and name> /size:<bytes> /entries:<value 0 to 300> ) I thought would help did not.

Perhaps you could write a C# app that tracks System.DateTime.Now every minute or whatever (with a sleep command) and if the current time is more than 30 minutes away from the previous time, it could use Process[] processlist = Process.GetProcesses(); and spit out a list to a log file of what processes are running when it detects the jump. Such an app would be exceedingly simple to write, but also not very useful, since a large number of microsoft processes are always running in the background.


Does your BIOS maybe also have Time Zone settings???

[Jorpho]

I have yet to see any BIOS with timezone settings.

I may resort to a programmatic solution of some sort next time, but if a new process was spawning somehow, I'd probably see it in the task scheduler, wouldn't I?

[dudiobugtron]

Does anyone else use the computer? Seems like a pretty fun practical joke to play, especially if they're reading this thread as well.

[Jorpho]

Nope, it's just me.

Now, I did see this the other day when I restarted my computer. I saw something similar once the last time my clock was jumping around:

Spoiler:

But still, I restarted my computer a couple of times last week when the clock was still jumping around and never saw something similar, and as I said, it's been pretty stable again lately. Also, as I said before, if the CMOS battery was dying, a jump of exactly eight hours every time wouldn't seem to make any sense.

[freakish777]

Nope, it's just me.

Now, I did see this the other day when I restarted my computer. I saw something similar once the last time my clock was jumping around:

Spoiler:

time.jpg

But still, I restarted my computer a couple of times last week when the clock was still jumping around and never saw something similar, and as I said, it's been pretty stable again lately. Also, as I said before, if the CMOS battery was dying, a jump of exactly eight hours every time wouldn't seem to make any sense.

Unless your BIOS does in fact have a time zone and the default is 8 hours backwards...

[Wnderer]

Hours = 11 in binary(00001011)
Hours = 03 in binary(00000011)

I'm not sure how time is stored in CMOS, but if it is not stored as Unix time but with separate Year, Month, Day, Hour, Minute, Sec, and Milliseconds, a missed high bit would set the clock back 8 hours. A week CMOS battery might have something to do with it. Either not being able to hold the bit in memory or not being able to provide a high enough one bit or a fast enough rise for the first 1 bit after all the zeros if it was reading MSB first. Okay maybe this is a lot of conjecture but I would try replacing the CMOS battery if the time change really bothered me. I might just ignore the time change though.

Of course, this could be caused by an extremely localized temporal anomaly.

[EvanED]

Of course, this could be caused by an extremely localized temporal anomaly.