External hard drive not recognized windows 10 : How to format and fix it

Connecting your hard disk to your PC and seeing that it is not recognized or returning an error is very unpleasant. Disconnecting and reconnecting the device this time did not work and it is necessary to act differently. This guide analyzes the best ways to format HDD and restore its functionality.

Warning: formatting is a simple but delicate procedure. This, in fact, will result in permanent deletion of data from the external hard disk.


Format external HDD not recognized on Windows

Everyone knows Windows, but often not enough to be able to solve the problem alone or figure out which way to choose. Here is how:

Assign a new drive letter

These are extremely rare cases, but it is possible that the computer, confused by the continuous use of devices, can generate conflicts between the letters of unity.

In this case, whatever the version of Windows available, the steps will be simple but numerous. First, look for the partitions in the search bar and click on the result that best suits you. This will open the disk management where it will show the internal and external memories available to the PC at that time. It is now necessary to identify the external memory to be formatted. Under the heading Disk 1 there is the writing Removable. This is where the affected memory is located. At this point, right click and select (if selectable) Change letter and drive path. Assigning a new letter is simple and intuitive and should solve the problem. Choose the letter you want and continue by finishing the operation. Yes, but it did not succeed, then formatting is required by assigning a new file system. 

Assign a new file system

If the drive letter was not the problem, it is clear that it is time to assign a file system: without it the operating system is unable to write any data on the external memory.

  • Go to the disk management as described above and right click on the memory.
  • If this needs to be initialized it will appear, in the drop-down menu, initialize, otherwise it will appear formatted.
  • Then select what appears and in case of initialization check MBR and continue.
  • Now to allocate the memory, then to make it accessible, you only need to select from the New simple volume drop-down menu. You will be asked to choose between NTFS and FAT32.

NB because the NTFS format could give compatibility problems with an Apple operating system. If the maximum file size to be inserted is 4GB then FAT32 is recommended. In a few moments the disk will be formatted and ready for use.

Command line

Avoiding the scams of the graphical interface is simple. It is also possible to format the hard disk from the command line ( CMD = Command Line Interface) using a utility already present in the operating system. This is DiskPart that requires expertise and concentration to avoid disasters.

Run diskpart.exe by first pressing the Win + R keys. It will open the command line where to type the list disk to have an overview of the available memories with their dimensions. Substantially it is this last detail that allows an easy identification of the memory of interest. After that, type select disk n (n = disk number) and press enter, then type clean and press enter again. Now the hard disk is totally empty, as if it did not exist. We need to allocate the memory by creating a primary partition. Type create partition primary and, after sending, format FS = FAT32 quick or format FS = NTFS quick ( quick identifies the quick format and can be omitted). Now the hard drive is ready. All that remains is to type exit to exit the utility.

Format external HDD not recognized on MacOS

The instructions for the Cupertino operating system are simple and traceable to those of the rival operating system. So let’s see how to use Disk utility and diskutil.

Disk Utility

Disk Utility provides a graphical interface suitable for the average user. Search for the tool in the Spotlight search barand open it. The screen is more organized and understandable if compared to the same on Windows. Go in search of the external memory of interest, based on name and size, in the External section of the left column (see photo). After selecting the memory click on initialize. A form will appear where you can enter the desired file system. Enter the name of the HDD and select as an MS-DOS or EXFAT file system to maximize compatibility with other operating systems (MS-DOS corresponds to FAT32 and imposes limitation of maximum 4GB per file, unlike EXFAT does not impose such restrictions). If the initialize button is not active, just click on activate and complete the procedure as explained.


The thrill of programming and hacking also invades MacOS. Open the terminal by searching for it with Spotlight and type diskutil. A list of the commands that can be given to the utility will appear. Among these will be used list. Then type diskutil list and a list of all the memories connected to the PC with the relative dimensions will appear. To identify your memory, consider only those that appear under the heading external. Once identified, remembering the ID (disk1, disk2, etc ..), type diskutil eraseDisk FAT32 Name disk1 replacing disk1 with disk ID and name the desired name. Wait for the procedure to be completed and verify the correct operation of the procedure by disconnecting and reconnecting the hard disk.

Format external HDD not recognized on Linux

Linux is the absolute operating system suitable for geeks. Probably the need to format a hard disk is due to an unsuccessful installation of a new OS or to some problem of unknown origin. Linux offers its users GParted and Fdisk from the command line.

Use GParted

It is a must in Linux operating systems and turns out to be the simplest of software compared to other OS. Since formatting is a delicate procedure, once the program is started, it will be necessary to authenticate itself by accessing it as an administrator. From the drop-down menu at the top right select the HDD you want to format and then right click on New partition. Now you need to enter the desired file system by choosing between FAT32 or NTFS. Keep in mind, as already mentioned, that the former has a better compatibility with other OS but a limit of 4GB maximum file size and that the latter is not compatible with MacOS but has no restrictions on the maximum file size. Enter the name and proceed with the termination of the operation. Now the HDD should automatically be recognized by the operating system. However, an error message may appear to warn of the lack of a partition table. Then run Devices> Create Partition Table, select MS-DOS and then applyOnce the operation has been completed, repeat the procedure described at the beginning.

Use Fdisk

It is the equivalent of GParted, but on the command line. Open the Terminal by running it from the menu and type sudo fdisk -l. Now it is necessary to identify the affected memory, using the dimensions specified by the Size entry, also remembering the ID useful for the subsequent steps (eg ID = sdb). For formatting, type sudo fdisk/dev/ sdX replacing the previously marked ID with sdX. Type d + ENTER  to delete the existing partition and then type n + 5x ENTER (5x = 5 times) + n + ENTER + w + ENTER. Now you need to set up a file system by typing sudo mkfs.vfat -n “DeviceName” -I / dev / sdX1 + ENTER (FAT32) or sudo mkfs.ntfs -n “DeviceName” -I / dev / sdX1 + ENTER (NTFS) (replace the previous ID to sdX1). You can also use other file systems such as EXT4reiserFSBTRSF, or HFS. In the general command sudo mkfs.filesystem -n “DeviceName” -I / dev / sdX1 + ENTER then replace vfat, ntfs, reiserFS, btrsf or hfs as needed. Let’s remember, once again, the properties of FAT32 and NTFS:

  • FAT32: maximum compatibility, maximum limit of 4GB per file
  • NTFS: not recognized by MacOS, no file limits

Now that the HDD is ready, just unplug it and reconnect it to make it work.

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