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It’s well known that USB flash drives are supposed to be ejected before removing them. Your computer will often display a scary warning if you fail to safely eject the drive. But do you really still need to do this? What happens if you don’t?

Let’s take a look.

Different Protocols

First, we need to consider three different protocols 10 Networking Terms You Probably Never Knew, And What They Mean 10 Networking Terms You Probably Never Knew, And What They Mean Here we'll explore 10 common networking terms, what they mean and where you are likely to encounter them. Read More your drive may use when connecting to your computer. Two of them don’t need to be ejected at all.

mounted flash drive


Smartphones, cameras and other media devices that connect via either MTP or PTP can be disconnected simply by pulling out the USB plug without any damage to its storage.


Why Would You Need to Eject a Drive?

If your drive (or device) connects using the USB Mass Storage The Office Worker’s 101 Guide to a USB Thumb Drive The Office Worker’s 101 Guide to a USB Thumb Drive Flash drives today are not just about storing your important files: you can use them to run programs and even entire operating systems. Read More protocol then it should ideally be ejected. Although, as we’ll see, it differs slightly depending on whether you’re using Mac or Windows.

This applies even if you’re not actually using the device at the time.

The reason is because operating systems use a process called write caching. The operating system doesn’t always write a file to a drive immediately, but instead caches it and waits until it has multiple write operations to complete.

Doing these all at once improves performance, but if the cache is still full when you remove the drive, your data will become corrupted. Clicking the Eject button causes the cache to be emptied and any remaining data to be written to the drive.

That’s the reason why there’s often a delay of several seconds between ejecting the drive and being notified that it’s safe to remove it.

There are also potential issues with the abrupt removal of the power supply from a flash drive. Flash memory is susceptible to this, and it can cause parts of the drive to become corrupt.

Ejecting a Drive on a Mac

All this information applies to flash drives plugged into Mac computers, and to Linux machines as well.

These use write caching to deliver superior performance.

Ejecting a drive on a Mac is a simple process. Just drag the flash drive icon — that will have appeared on the desktop when you first connected it — into the Trash. Or click the Eject icon next to the drive name in a Finder window.

ejected flash drive

Ejecting a Drive in Windows

The situation with Windows is slightly different.

By default, Windows has write caching disabled. This results in slightly inferior performance when writing to the drive, but also adds a layer of security to the many users who forget to ever eject them.

If you’re not concerned about the risks, you can activate write caching on drive-by-drive basis.

To do this, locate the Device Manager on your PC — Control Panel > Hardware and Sound > Hardware and Printers > Device Manager on Windows 7; or right-click in the bottom left corner of the screen and choose Device Manager on Windows 8.


Right-click on the attached drive, click the Policies tab, change the removal policy to “Better Performance”, and enable write caching setting accordingly.

If you do this, you will always need to ensure you eject the drive via the Safely Remove Hardware option in the system tray.


And just to note, write caching is already enabled on internal drives by default and you shouldn’t disable this as you will notice a significant drop in responsiveness.

A Quick Word about Hard Drives

So far we’ve been talking about flash drives. If you’re using an external hard drive then you should always eject it before you disconnect.


Most modern external hard drives will also be powered over the USB connection. Cutting the power while the drive is in use could cause a head crash Hard Drives, SSDs, Flash Drives: How Long Will Your Storage Media Last? Hard Drives, SSDs, Flash Drives: How Long Will Your Storage Media Last? How long will hard drives, SSDs, flash drives continue to work, and how long will they store your data if you use them for archiving? Read More .

This is where the head, which swings back and forth just above the spinning disk to read and write data, comes into direct contact with the disk and causes physical damage to it.

This can render large chunks of the disk unusable, or even the entire drive. Learn how to properly care for your hard drives How to Care for Your Hard Drives and Make Them Last Longer How to Care for Your Hard Drives and Make Them Last Longer Sometimes an early death is the fault of the manufacturer, but more often than not, hard drives fail earlier than they should because we don't take care of them. Read More .


So, to summarise, media devices don’t need to be ejected. Neither do flash drives on Windows, unless you’ve specifically changed the settings for them. Drives on Macs should always be ejected, as should hard drives.

Improper removal of drives could cause data corruption, or in worse cases, put the integrity of your drive at risk.

Do you always eject your drives before unplugging them? Have you ever suffered data loss or other problems as a result of not doing so? Let us know in the comments below.

Image Credits: External hard drive via Karen

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