Why is it necessary to "Safely REmove" any hardware

sahildave1991 said:

Can anyone tell me the exact reason why is it necessary to SAFELY REMOVE any hardware ex pendrive, memory card, external harddrive etc.

The main reason is to ensure that the operating system has finished writing to the device therefore enabling it to be removed

Safely remove devices from your computer

Safely remove devices from your computer

If you unplug a storage device or removable drive from your computer while it's transferring or saving information, you might risk losing some information. Windows provides a way to help you safely remove such devices.
Most USB devices can safely be unplugged and removed. When unplugging storage devices, such as USB flash drives or external hard drives, make sure that the computer has finished saving any information to the device before removing it. If the device has a small light that shows when it's use, wait a few seconds after the light has finished flashing before unplugging it.
If you see the Safely Remove Hardware icon in the notification area, at the far right of the taskbar, you can use this as an indication that your devices have finished all operations in progress and are ready to be removed. If you don't see the Safely Remove Hardware icon, click the Show hidden icons button to display all icons in the notification area.

The notification area, at the far right of the taskbar

To safely remove a certain device, click the Safely Remove Hardware icon , and then, in the list of devices, click the device that you want to remove. Windows will display a notification telling you it's safe to remove the device.

Note

You can also safely remove devices from the Computer folder. Click the Start button , click Computer, right-click the device you want to remove, and then click Eject.