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Q. Is Data Safe in Sleep/Standby/Suspend Mode? Getty Images

Q. Is Data Safe in Sleep/Standby/Suspend Mode?

Q. What happens to running programs when Windows goes into standby mode? Is the data kept safe?

A. In general, Standby usually refers to a low-power state that suspends system operation without shutting anything down. It then trickles just enough power to the system to keep all volatile system memory (RAM) intact. When the PC resumes, full power is returned and things pick up from where they left off, without missing a beat.

Standby’s benefit is reduced power consumption with a fast resume. On the other hand, it leaves everything in live memory; if you turn off the power (or pull the plug or lose electrical service, etc.), any unsaved data will be lost.

But note that terms such as “sleep,” “standby,” “suspend,” and so forth can be fuzzy — they can mean different things on different systems.

Microsoft offers some specific PC power-state definitions on an MSDN page. Those definitions are usually accurate for Windows, and for hardware OEMs and software publishers who follow Microsoft’s lead.

Of special note is the improved form of standby supported by Windows 7, 8, and 10 on compatible hardware. It’s called hybrid sleep.

When your PC enters hybrid sleep, Windows first writes a full hibernation file, just as if the system was turning off. But instead of turning off right away, the PC initially goes into a conventional standby/suspend/sleep mode.

Thus Hybrid sleep keeps two identical copies of all live data: one copy is safely stored in the hibernation file and the other copy is kept alive in RAM with a trickle of power.

A PC in hybrid-sleep will usually stay in this dual state for about three hours (adjustable via Control Panel’s Power Options applet). If you press a key, click the mouse, or otherwise wake a PC while it’s in this initial phase, the system will usually resume almost instantly, using the data still stored in RAM.

If there’s no activity within about three hours (or whatever time you set), the PC will shut down fully to save power. But no data is lost because everything was preserved in the hibernation file.

When you return to the PC, it resumes by activating the drive and writing the large hibernation file back into memory. This usually takes a few seconds or minutes, depending on the amount of memory in use and the speed of the drive. But the end result is that you can resume exactly from where you left off, with all files, data, and screens just as you left them.

Note: In addition to automatic power savings, hybrid sleep also provides an automatic safety net against accidental power loss during sleep. If electrical trouble of any kind erases the in-RAM data, the copy on the hard drive should remain unaffected.

In short: a “Hybrid sleep” option offers power savings, fast resume, and improved data security. It’s truly a superior form of standby; it’s worth using if your PC supports it!



Editor's note: We feature an abridged Q&A from Fred Langa's LANGALIST, a column available exclusively to paid subscribers of the Windows Secrets newsletter,. What you see here is just a small sampling of what Langa's writing for the newsletter — go here for more information on how to subscribe.

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