Another look at the impact of the coming 2015 leap second on Microsoft products (not much)

Drawing of a man holding back the hands of a clock with the caption "You can't stop time"A month from now, we should be looking back at the press that decried the coming Leap Second (caps my own) as a veritable Y2K and wondering “what was all that about?” As I’ve shared previously (see “What’s all this about the Leap Second”) I’ve learned quite a bit about how Microsoft products and services address the addition of a new leap second. Most often, issues of time and date are addressed by the groups involved in managing the Windows OS, plus in this instance by the team managing the Windows Time service. Many of our products and services rely on the underlying OS for time and date, much like the support for daylight saving time and time zone support. There’s a great TechNet post that covers How the Windows Time Service Works.

What you likely need to know: On the Windows Client, current supported versions of Windows are plumbed to deal with such leap second changes via an NTP ping in the Windows Time service (a.k.a. W32Time), as I summarized here. As you may know, W32Time handles regular clock sync, and as root time sources are updated, changes propagate through NTP and adjust network synched clocks. I outlined much about what you may want to know in my post on the story around Leap Seconds and Windows. Essentially, set your PC to sync with an Internet time server via the Control Panel in Windows 7 (as noted here), or in the PC Settings for “Time and Language” in the Control Panel on Windows 8.1 (as shown here), and you’re good to go. (If you’re device is part of a domain – such as PC provided by your company for business – then your clock sync is likely managed by your IT administrator, so again, you should be good to go.)

Background on how a leap second is added: When a leap second is to be added, a notification is broadcast on the day of the event (sometimes in the hour prior) via an NTP flag from the NTP server to all NTP clients. Time services (e.g., sync with authoritative, atomic clock time servers such as those maintained by the National Institute of Standards and Technology (a.k.a. NIST, at These facilitate regular clock sync, and as the root time sources are updated, changes propagate through NTP and adjust network synched clocks as well. Technically, IIRC, the leap second is applied by NIST on NTP as a second iteration (a repeat, actually, in binary) of the final second of the day, and would look something like this: “23:59:58… 23:59:59… 23:59:59… 00:00:00UTC”. (BTW, some systems interpret this last second as 23:59:60.) Think an abbreviated, one second version of the issue Emily Blunt faced in Edge of Tomorrow, but without all the bloodthirsty aliens and general mayhem.

How a leap second is reflected in Windows: Contrary to one post I recently read, Microsoft doesn’t implement a leap second time zone by time zone – in other words, in a rolling fashion, like the way we watch new year celebrations count down around the world. Essentially, the leap second occurs at the same time everywhere. Just when your individual device syncs with NTP will likely be different from others. Windows devices that are joined to a domain will attempt to sync with the domain hierarchy. Consumer devices that are not domain joined, sync time less frequently or have intermittent network connections sync the clock most commonly to the Microsoft NTP server, As these systems do not sync the clock frequently, we’ve stated that “it is impossible to guarantee time accuracy on computers that have intermittent or no network connections.”

Devices that are synched with will eventually sync to the current, accurate time reflecting the leap second. As syncs with NIST time servers, Windows devices are generally accurate and in sync subsequent to the addition of the leap second. Many devices will sync within the first few seconds of 00:00:00 UTC (which some may refer to as “midnight UTC”) on June 30, 2015 / July 1, 2015 as they ping the service. But of course, not all systems sync at or close to 00:00:00 UTC. Microsoft has outlined that W32Time service is not a full-featured NTP solution that meets time-sensitive application needs (see Microsoft KB 939322, Support boundary to configure the Windows Time service for high-accuracy environments). Companies that require critical timing systems usually implement a specific reference clocks that provide highly accurate hardware clock, which when used with Windows, use their own incredibly accurate clock drivers. Whereas Windows is supported to be accurate within something like 3 seconds, these clocks are accurate to within <1s. (If you want to get all nerdy, my friend, Matt, reminded me of my desire for a Meinberg clock, and a great summer project you can DIY with your kids.)

How the leap second is reflected in services:  Various cloud systems obtain NTP sync in much the same way. How leap seconds are applied to and appears on a local machine clock may be different, but this is well documented and understood in Windows, upon which Azure has its origins. (More on that in a second – see also the info in Microsoft KB 909614, How the Windows Time service treats a leap second, and KB 939322, Configuring the Windows Time service for high-accuracy environments.)

In speaking with the Azure team, I learned the service has been designed to be resilient to clock discrepancies across our numerous infrastructure components and regions. Azure has proven application compatibility for handling leap seconds given it uses the Windows time-synchronization protocol, which is used by all Windows systems including the Windows client OS, Windows Server, Windows Phone, and Hyper-V. When the last leap second adjustment was made (back on June 30, 2012) we had no reports of leap second issues for any of our products across Windows, Azure, or the customer applications running on Azure. Similarly, I understand that other Microsoft services, including as Office 365, Dynamics CRM Online, Intune and Azure RemoteApp services, aren’t affected by a  leap second change. I’ll add additional information here as I come across it.

Generally, Microsoft products (e.g., Exchange, Office) and most/all third party apps rely upon W32Time to provide an authoritative view of time, using UTC rather than local time (the time you see displayed by your Clock app and in the Date & Time display). As long as the OS is able to manage the leap second change, dependent applications should generally be fine: there could be implications for apps or services that do not follow standard clock implementations. If an app or service uses another time sync method or has other time dependencies then there could be an impact (e.g., presenting an app with a time reference of 23:59:60 when it doesn’t expect to see seconds greater than :59). More info on some of these concepts with appropriate links here.

Article also available at

[edit: added information in ¶2 on domain-joined devices; added detail in ¶3 on the binary nature of the leap second via NIST]


Available now: December 2014 cumulative time zone update for Windows operating systems

Is it December already? That means that holiday treat we know at the December cumulative time zone update for Windows operating systems is out, available as kb 3013410. As noted, this update replaces the previous August 2014 CU 2981580 and includes all the time zone and daylight saving time changes released as hotfixes since then, including the monumental changes we saw in Russia in October. (ICYMI, Se my post from September.)

The following changes were made since the previous Windows cumulative time zone update:

  • Russia time zones: Russia announced that it would change its existing time zones on October 26, 2014. This change included seven updated time zones, three new time zones, and two existing time zones that merged into one.       (     
  • Fiji Standard Time: Fiji announced that the country’s new daylight saving time (DST) schedule would start on November 2, 2014 and end on January 18, 2015. The previous DST start date in Windows for the Fiji time zone was October 26.(     
  • Cape Verde Standard Time: We have changed the name of the “Cape Verde Standard Time” time zone to “Cabo Verde Standard Time.” The display name for this time zone is now “(GMT-01:00) Cabo Verde Islands.”

So what should you do to make sure that your computers are ready for the change?

Most applications and services reference the underlying Windows operating system for their date and time related rules, with some exceptions. We outline the various software updates to select Microsoft products (including various releases of the Microsoft Windows operating systems, Microsoft Office and other applications) on the Microsoft Daylight Saving Time Help and Support Center. There, we have information and links to updates for various products in mainstream and extended support affected by this change, as well as other various changes to DST offsets and time zones around the world.

If you use Microsoft Update on your PC at home, chances are you’re already covered. The latest update from October may already be installed on your PC if you have turned on Automatic Update in Windows. This ensures you’ll get the latest security and other important updates from Microsoft automatically. If you’re not sure if the update has been applied, visit the Microsoft Update site for more information.

If someone manages your network at work, it’s likely the needed updates are schedule to be deployed to your computers and devices, if they haven’t been installed already.

For IT professionals managing PCs, servers and Microsoft software installations, please visit for more details. Also, visit the support websites of any other software companies to see if you need to apply any updates. It’s not just Microsoft software that may require updates. Additionally, for the latest change in Russia, we provided specific details and guidance at

While Microsoft’s Services infrastructure will be updated to reflect DST changes, it’s important that your computers — both clients and servers that interact with these services — also have the latest Windows cumulative updates for DST and time zone changes applied in order to ensure data integrity.

As always, thanks to the good folks in Windows and those across the company working to help manage time… particularly the number of daylight saving time and time zone changes that come in from various corners of the world. You can find this and much more documented over at and over on the Windows blog at



Windows Updates for New Russia Time Zones Now Available

As I highlighted last month, the Windows team in OSG have supported the new Russian time zone changes. What with the changes to the Ruble symbol and now the eleven new time zones and move away from daylight saving time, perhaps I should rename my blog…

As noted, the target release date was September 23, 2014, which was met: the Russian Federation time zone update is available now at: and on the Microsoft Russia site at

Please note that if you’re using any of the current Russian time zones or doing business with customers or partners in the affected territory, the guidance we received from the Russian government that the change will occur on October 26, 2014 at 2:00 am local time. When we see time zone offset changes (due to daylight saving time) and time zone revisions, the time change is often executed with the next click of the clock after 1:59:59h. (Well, not always: Samoa made its historic move at 23:59:59.)

Consumers and Small/Medium Business customers should ensure that Windows Update is turned on if you don’t have someone managing your computer. The update packages for all currently supported Windows platforms are available via Windows Update. If someone manages your network at work, it’s likely the needed updates are schedule to be deployed to your computers and devices, if they haven’t been installed already.

If you live or work in some of the regions affected by this change, you may want to check the time zone setting on your device (available in the Settings on Windows 8). In some cases in the affected areas, your device may be set to a new time zone. Some other applications may require changes or adjustments to the time and date information. In some cases, all the necessary changes automatically and you will need to take individual decisions in specific cases. For information on updating software from other vendors, please visit their Web sites.

For more information, please visit – details will be added to the site on other products and services as available.


Microsoft Account Gets More Secure with Two Factor Authorization

ICYMI, your Microsoft Account will get more secure as the team rolls out a new upgrade which includes two-step verification, as noted on the Bing newswire. This will improve the security of the devices and services currently used by more than 700 million people worldwide, including Windows PCs, Phones, Xboxes, and services like, SkyDrive and Skype.

Microsoft has increasingly focused on delivering connected devices and services that are currently used by more than 700 million people around the world. A Microsoft account is the key that unlocks your experience across these products—from your Windows PC to your Windows Phone, from Xbox to, from SkyDrive and Skype to Office and much more.

Given this critical role for Microsoft account, we remain vigilant in working hard to protect your account, which is why we’re adding an option so you can enable two-step verification to further protect yourself. You should see this option show up in your account in the next few days. You can enable this capability at

Two-step verification is when we ask you for two pieces of information anytime you access your account — for example, your password plus a code sent to a phone or email on file as security info.

More than a year ago, we began bringing two-step verification for certain critical activities, like editing credit cards and subscriptions at and, or accessing files on another one of your computers through For these scenarios, two-step verification is required 100 percent of the time for everyone, given the sensitive nature of these tasks.

Read more from Eric at the link above.


RSS feed reader blues? Get your feed in Microsoft Outlook and Office 365

ICYMI, Google Reader, Google Voice App for Blackberry, Google Cloud Connect, and Snapseed Desktop are shutting down. Hilarity ensued on the Internet with the melt down on social media over the change. As Danny Sullivan noted here, “Google should have done better by Google Reader & Google users than to bury its closure in a “spring cleaning” post.”

All the talk about RSS Readers reminded me of how important it is to listen and respond (this from 2011 via TechCrunch).

But I digress.

If you’re impacted by this announcement, have no fear: there are options, many great options.

First off, Good advice from Sara Hevans (@prsarahevans) on how to backup your Google Reader account

Once you’ve backed up, you’ll need a new reader.

With all these options, you may already have an option on your desktop: you can also use Outlook in Microsoft Office to subscribe to an RSS feed as noted here.

So if you’re looking for RSS subscription and management? our own Office 365 Home Premium has that:

Quick links:

Tags: Microsoft, RSS, Outlook

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