Ask LH: How Long Can A Hard Drive Hold Data Without Power?

Ask LH: How Long Can A Hard Drive Hold Data Without Power?

Dear Lifehacker, After a few tragic ends to some photos (poof, gone), I’m trying to get a good offsite backup plan in place. I was curious, and haven’t been able to find a definitive answer in any of my resources: If I copy data to a standard SATA hard drive, and then unplug the hard drive and store it, how long will that data remain intact? How bout on a flash drive? Signed, Concerned Packrat

Photo by Carl Berkeley.

Dear Packrat,
Hard drives, unlike RAM, don’t need electricity to keep data once it’s been written. Because of this, a standard SATA drive can store and maintain your files for extremely long periods of time, even if it’s shelved in a closet away from a computer. The actual storage lifespan will vary, though.

The standard hard drive warranty runs about five years. That number is assuming regular use, so if a drive were to be plugged in and have data written to it infrequently, and stored in a dry space with optimal temperatures, there’s no reason that it couldn’t last far longer than that — in the range of seven or even eight years. Always keep the drive safe from large magnetic fields, since they could help to degrade the data much more quickly, and keep that temperature rule in mind, since there are movable parts with grease that could dry up and crack in the wrong conditions. The actual temperature range varies from drive to drive, but keeping it somewhere between 10C and 40C is a pretty safe bet.

Solid State, or “Flash” drives, though still new, would theoretically last longer. That being said, you should never count on more than a solid eight or nine years, because the whole point of data storage like this is to keep it safe, not to take chances. Technically, it’s possible for a NAND flash drive to last far longer than a decade in storage, but every unit is made differently, and some might have cheaper components than others. As for heat and magnets, an SSD will fare much better than a traditional hard drive (it would take a supermagnet to even begin to affect one).

The basic thing to remember here is to check the data on the stored drives once every few months, just to be sure that it’s still intact, and to invest in a replacement for the drive every few years. Other than that, all you can do is keep them safe, and hope for the best.



  • I’d be more worried about finding a working host computer in 10 years time than the drive not working. Keep in mind that 5 years ago IDE drives were still the main drive, and 10 years ago SATA didn’t exist. Now you would be lucky to find a motherboard that supports IDE drives.

    The best thing you can do is make NEW backups every 3-5 years on something that is current at the time. You don’t have to spend a fortune. $50-100 odd should be enough. Keeping in mind that what you pay $100 for now won’t take up a quarter of the space on a drive you buy in 4 years time.

    If you continually upgrade your backups every few years, you should be able to keep “everything” on the one drive. Unless you’re storing video, but one drive should be enough for all photos, docs etc.

    • Agreed, rolling backups are the best long-term solution. Every few years, migrate all your old data from the old backups to the new – if your data still fits on dvd, you can just re-burn a bunch of dvds. If you’re using hard drives, grab a few cheap drives every couple of years and retire the old ones.

      The classic home-backup system involves three drives – two local, that you alternate backing up onto, and one offsite (ideally in a fireproof safe in a secure location). Every few months, swap the offsite drive with one of your local drives. After three years or when the first drive fails- whichever comes first – replace all the drives and start again.

      Of course nowadays you can get a lot of the benefits of this with one backup drive and offsite cloud storage, but I’m guessing that gets fairly expensive if you’re talking about terabytes of data.

  • I agree with Blake – you’ll want to make sure you have a host computer that can still read it.

    If I was going this route I’d pop the hard drive in a simple USB hard drive enclosure – they don’t cost much, it’ll provide some additional protection and it’ll make it easier on the connection front in years to come. USB ports aren’t being phased out anytime soon and while the technology have developed over the years they’re good at maintaining backwards compatibility

  • Oh yeah sorry meant IDE ‘facepalm’. Its not saying that i didnt migrate the data when i upgrade to my first powerbook, just that the IDE drive still worked. I agree that you should a solid migration plan, however it is unrealistic that less technical users can achieve this.

  • I was talking to a level 2 tech support rep at WD today regarding installation of a My Book Essential HD (magnetic, not SSD). I mentioned that I archive video data files on these drives and store them in a closet. He told me that, left unplugged, the data on a magnetic drive could be lost in as soon as seven or eight months. He said the drive needs to be plugged in periodically so it can maintain the charges it uses to store data on the platters. He had spoken with one customer who stored a drive in a safety deposit box for less than a year and the data had degraded to the point that it was not accessible. I spoke to another rep a couple of hours later, and, while he thought the first rep may have overstated the potential problem, that it was indeed a problem and magnetic drives should be run from time to time. I also have accessed drives that haven’t been used in a year or more with no problem, but apparently it can be a problem to store a drive long-term without power.

  • Lee M, sorry but that tech support guy has no idea what he is talking about. A magnetic hard drive does NOT have to maintain a charge (you can take that from an actual engineer)!

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