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Will a power loss cause data loss on SSDs?

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If I buy an SSD hard drive to replace my dead mechanical hard drive, what are the drawbacks? I have no UPS. If the electricity goes out during writing, will the data be gone like a USB flash drive?

I’ll admit that the phrase “like a USB flash drive” in your question bothers me. It kind of implies that flash drives always lose their data on power loss and that simply is not true.

Sudden power loss will actually affect all three of the different devices (physical hard drives, a Solid State Drive, or a flash drive) in pretty much the same way.

There are three things that can happen when power is suddenly removed from your computer while you’re using your hard drive.

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Nothing happens

The most common thing to happen is absolutely nothing.

It’s actually kind of reassuring in some ways. You turn the computer back on, the power returns, and everything picks up more or less where it stopped. It’s not something to be relied on by any stretch of the imagination, but it is one of those statistically happy coincidences that your machine is usually okay.

There’s some data loss or corruption

The next most common thing to happen is some amount of data loss or corruption.

Perhaps a file that was being written to at the time of the power loss might find some of its data missing or garbled. The file system could report that it’s missing information, so you may end up losing files or having other things disappear.

And this is true regardless of what kind of drive you’re using.

ExplosionThere’s massive data loss

Of course, the rare, but still possible option is that you could have massive data loss.

If the computer happens to be writing at exactly the wrong place at the right time when the power goes out, it’s conceivable that critical information could be lost. It’s also possible in some cases – again, rare – that some actual physical damage could occur.

Most of these devices are very well protected from that kind of a thing and what we’re usually looking at is data corruption or loss. In most cases, recovery is usually possible with a combination of tools like Recuva (which I’ve recommended in the past for being able to find and recover deleted files) as well as things like CHKDSK to rebuild the system file structure and have that working once again.

Prepare for problems: Backup

Ultimately, the best thing that you can do is make sure that you are appropriately backed up. Anything can happen at any time. Your hard drive can completely fail without warning. And that’s true of physical hard drives, Solid State Drives, or USB flash drives.

AJAX progress indicator
It doesn’t necessarily take the power going out (although the power going out certainly doesn’t help). If you’re in an area that’s prone to power problems – even minor glitches – I actually recommend that you invest a few dollars in an uninterruptable power supply (UPS). That provides power to your computer for some time after your main power has gone out. How long it does depends on how big a UPS you get and how much power your computer uses.

But the important thing is that it can give you enough time to shut down your computer cleanly.

In fact, some of them have interfaces so that they will notify your computer that the real power has gone out and the computer can shut itself down cleanly.

I really don’t think that there’s a tremendous amount of difference between the drive technologies when the power goes out. The power going out is just kind of a scary thing. It can do bad things – or nothing at all – on all three of the different media types.

2 comments on “Will a power loss cause data loss on SSDs?”

  1. I would imagine the hard drive might have slightly more potential for more serious damage as a power loss at an inopportune time might cause a head crash (the write head scratching the hard drive.)

  2. Good article. One point of clarification: some people seem confused regarding traditional storage and RAM, much like confusing memory with drive space. All drives — whether they be mechanical or solid state, full size or USB thumb drive — have data *written* to them, and stays until overwritten or deleted. RAM (memory), on the other hand, *does* disappear after power is cut. Thus, the need to save regularly, and MS Word’s (and other app’s) default behavior of auto-saving every few minutes. Once saved to a drive (any drive), said data should be safe from a power failure.

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