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When formatting a disk you have the option for a "quick" format. We'll look at what's quick about it, and when you should and should not choose it.

I recently purchased a 64-bit Windows 7 Ultimate. When I try to format my flash drives, quick format is checked by default. In order to full format I uncheck the quick format box. However, a full format takes several minutes. Is there any disadvantage in using just quick format every time I format my flash drives?

Quick format is typically a lot faster, particularly when used on actual hard drives. The reason, of course, is that it does a lot less work.

I'll look at the differences between a quick and a full format, and why you might want to choose one over the other depending on the situation.

And I'll also talk about why flash drives are a special situation when making that decision.

Full Format

When you format a disk without specifying that it is to be a "quick" format, it becomes a full format. A full format:

"Essentially a full format writes data to every possible place that data can be stored on the drive."
  • Writes control information to the very first sectors of the drive.

  • Creates an empty "root" directory of files and folders on the drive.

  • Depending on the format chosen, may write additional file system overhead information, as well as the initial volume label on the drive.

  • Writes data to every sector on the drive, and marks as unusable any sectors which fail to be written to.

It's that last step that takes all the time. Essentially a full format writes data to every possible place that data can be stored on the drive. The side effect, of course, is that whatever was written there before is overwritten.

Quick Format

You can probably guess that a quick format is everything a full format is, except for the last step. It:

  • Writes control information to the very first sectors of the drive.

  • Creates an empty "root" directory of files and folders on the drive.

  • Depending on the format chosen, may write additional file system overhead information, as well as the initial volume label on the drive.

In this case, the surface area of the disk is not overwritten, and whatever was stored in those areas of the hard disk remains.

Quick versus Full

It's worth reviewing that when you delete a file on the disk, the actual data that is stored on the disk is not removed - rather, the directory entry that says "this file's data lives here on the disk" is removed. The area that holds the actual data becomes part of the disk's free space and may then be overwritten if it's used to hold data for another file sometime in the future.

One metaphor is that it's kind of like moving out of an apartment. You can simply take your name off the door or list of residents, so your apartment is now "free". But if you've left all your stuff inside the apartment anyone can come along and take it. If someone else moves in, they'll get rid of your stuff, but until they do - there it sits. If you don't want people to have your old stuff you need to take the extra step of actually moving it out.

Formatting a hard disk is pretty much the same, except you're working on the entire building at once.

A quick format is sort of like simply taking the list of residents off of the front door and declaring the building empty. A full format takes the extra step of actually emptying the apartments of all their contents.

(Remember, it's a metaphor - it doesn't hold exactly - but it's a fairly simple way to get the overriding concepts. If we were to try to extend it we'd also start removing and moving walls while leaving all the stuff inside Smile)

Quick or Full: Which do you want?

Nine times out of ten, a quick format is sufficient. It's perhaps the fastest way to delete everything on a disk, and is very convenient for that. There's no need to take the extra time to write to every spot on the hard drive.

There are a couple of times when a full format might be a good idea, but even then there are alternatives for each:

  • You just got a new disk. A full format ensures that no one else's data is on it, and takes the extra step of identifying bad sectors before you start using it.

  • You're about to give the machine or disk away, or dispose of it. In this case, you really do want to erase not just the list of file names, but also overwrite the actual data on the drive so that it's not accidentally recovered.

All that being said, CHKDSK is a fine utility that you can use to scan your hard disk for errors at pretty much any time, and tools like SDELETE or DBAN are tailored to erasing information from the hard disk securely.

Formatting Flash Drives

As I said, flash drives are a special case.

The problem is that flash memory wears out the more you write to it - and a full format writes to all of it.

The result is that I would not perform a full format of a flash drive unless you had a very pressing reason. (I'd also not use tools like SDELETE to write multiple times to "securely" erase files, as that is meaningless on flash memory - overwriting once is enough.)

Article C4463 - September 25, 2010 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

Arthur Glazer
September 28, 2010 7:56 PM

Thumb drives are supposed to last through 100,000 or so cycles (write/erase). Chances are the drive will break or get lost long before that cycle has reached its end. I don't believe formating would matter.

September 28, 2010 8:13 PM

how quickly do flash drive wear out? More than a year or two?

Depends ENTIRELY on the quality of the drive AND exactly how it's used.

September 29, 2010 4:12 AM

hi, you can get the answer to this question here

September 30, 2010 11:17 AM

Thumb drives will only last 100,000 cycles if they have MLC (Multi-Level Cell) memory, sometimes called Extended Life Memory.
MOST drives use SLC (Single Level Cell) memory because it's much cheaper and smaller. The life for these are about 10,000 cycles.
Another usually overlooked factor is the USB port itself. The life cycles for these ports are about 1500 connections, so if you remove your drive every time you write to it; your life cycles will be 1500, not 10,000 or 100,000. Most users will wrongly assume it's the drive and not the port, just get a new drive and trash the old one.
And if you drop it, say goodbye to a few more cycles.

February 15, 2012 5:44 PM

I have an extra laptop hardisk from which I want to retrieve my data . When I connect the hardrive via USB cable to another computer I am asked to format the disk. Should I do Quick format ? If yes then what are the chances that the existing data will not be erased from the the hardisk ?


Mark J
February 16, 2012 2:05 AM

A quick format won't erase the data from the drive. It will only erase the index tables to the data. But since you want to recover the data, I recommend that you don't format the disk at all, as this would make recovery more difficult. You might try plugging this drive into another computer to see if it can read the data. If that doesn't work, running CHKDSK/ R or a disk recovery program like Spinrite might work.

July 30, 2012 5:51 PM

Leo, which creates greater wear on an empty flash drive: (1) formatting it or (2) a single iteration wipe of its free space? Thanks…

Quick formatting updates only the directory without actually writing to the entire media, so it would be significantly less. A full format and a disk wipe would be roughly equivalent.

February 19, 2013 2:57 AM

When I attached my 4GB hp Pendrive to my pc it ask me to format this. But neither it get to Access my USB Pendrive nor it allow me to format this. This case how can I access my this USB data and how can I format it later.

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