Kim Barloso

Windows can't complete formatting a flash drive: How to fix the error


When plugging in the flash drive a message appears: Unable to complete formatting. What to do with this error, should I ignore it?

The "Windows cannot complete formatting" error often occurs with new and previously used SD cards for mobile devices. The problem looks like this: The system prompts you to format the media but when you agree the error occurs.

In case the reason for the error is a software one, you can solve it by using special formatting software or the registry editor. Worse when the cause of formatting is hardware: for example, mechanical damage, then the medium cannot be recovered.

Content :

    Video guide

    Formatting software (SD Formatter and similar)

    It is not always possible to format flash drives using the standard Windows and other operating systems. Furthermore, "rough" formatting results in a severe shortening of the format medium's lifespan. For this reason experts recommend you use special tools for that purpose such as SD Formatter.

    For the formatting of a flash drive using the SD Formatter tools:

    1. Download the SD Formatter software, it is free and install it to your computer.
    2. From the "Formatter" menu, select your flash drive through the drive.
    3. Run the process in Quick or Deep mode.

    Video instruction:

    For most tasks, especially when your flash drive just refuses to be formatted the standard way, the Quick format option is sufficient. However if it fails you should try activating the Full-mode, it might work.

    Alternatives to SD Formatter: Mini Tools Partition Wizard, USB disk storage format tool. They are also free and perform as well as, and sometimes better than, the most popular formatting programs. The principle is the same: select the SD card in the Drive menu, perform a quick or deep format.

    Removing write protection from the Windows registry

    Specialized tools often help, but not always. With the "Disk is write protected" and "Windows can not complete formatting" errors, no specialized card formatting utility is able to resolve except for the professional ones. The average user will find it easier to understand how Registry Editor (Regedit) works in Windows than to pay for and learn complex commercial versions of the applications.

    Registry is a software storage of information on the operation of all software and hardware components of a computer. To deactivate software write protection, you need to go into the registry, fix the error and save the changes. How to do this:

    1. To open the registry via the Windows built-in editor, find "Run" at "Start" and type regedit.

    2. In the window opened, in the left column navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\.
    3. In the Control directory open or create, if not the subfolder StorageDevicePolicies.
    4. Open the context menu (pr. mouse button) of the StorageDevicePolicies folder and add the following parameter: DWORD(32-bit) (or 64-bit for 64-bit operating systems).
    5. Change the DWord name to WriteProtect, then put 0 (HEX) after it in the "Parameter" line.

    In place of regedit advanced users can use a third part registry editor. There is usually no difference for the result: To make edits in the built-in interface or to install proprietary programs.

    Reboot the computer and try to format the SD Card again, this should work. If not, may be the stick is defective on hardware level.

    Write-protected stick: Remove protection

    Checking the stick for Read/Write errors

    There are cases where the above methods may fail due to issues caused by viruses and malware. The most common cause is read/write errors. Again Windows itself helps to fix them:

    1. Insert the memory card into the memory card reader of the computer.
    2. From the "Start" menu select "Run" and type cmd in the textbox.
    3. In this command line enter chkdsk [letter of the USB stick]: /f /r and hit Enter.

    This will start a process whereby the selected memory card is checked for errors and bad sectors.

    The read/write errors occur and prevent the memory from being formatted in the selected file system. Once the check has been completed, reboot the computer and try each method described in this article once again. That should help.


    The memory card is in raw file system format. It is not formatted or deleted by any program. The cmd tells me that the operation is not allowed for the raw file system format.

    This means that the file system is not defined. Try to format it with SDFormatter or HDD Low Level Format Tool. It is also useful to check the disk for read errors with special programs .

    How to convert the RAW on an SSD to the NTFS file system, since these disks cannot be formatted. There is no information on the disk and it is not necessary to save anything.

    1. The sd card has to be checked for errors. To do that you would use the command chkdsk F: /f /r where F is the letter of the card.
    2. With diskmgmt you should check what partitions are available in the card and if necessary repartition it.

    You bought a new sd card, it worked fine for two months, then it would not load any /files, deleted any documents and now it would not format.

    Often the problem starts with a "Windows can not complete formatting the disk". If you are unable to find out why the flash drive is not being formatted, there is little point in finding out the real reason why Windows refuses to format the flash drive. Most likely, you can bypass the system's warning by using alternate formatting tools.

    First, read this article: Formatting USB Flash Drive to NTFS. This is useful material containing useful information on what formatting is, how to format it correctly, and which programs are designed to format it. Are there any formatting tools in Windows? What file system to choose: FAT, NTFS or something else? At the end of this article, answers to questions related to formatting flash drives.

    The microsd sony 64 gb flash drive can't be formatted. Files are deleted and written, but after re-inserting it into the card reader, everything is there again.

    The advice would be to take the card reader, connect the sd card to the computer and use the SD Format utility to format the card.

    The SD Format utility would be a universal solution. It is usually useful in the situations when the microsd would not format normally, and other tools fail to format.

    Transcend flash drive was used in the car DVR. After formatting the /files are not deleted. They are copied and deleted, but when I re-connect the stick the /files reappear.

    If you use Mac OS, the operating system automatically writes service /files to the stick, so even after formatting they remain (appear) on the stick.

    Try to format the card under Windows or use another formatting application such as SDFormatter.

    Some viruses may use your flash stick as a breeding ground for their malicious code, so it makes sense to test it for viruses by plugging it into your PC.

    In addition the DVR may write /files by itself, without your permission. Unfortunately you did not specify what kind of /files are copied to the USB stick, so we can not help you to find out the real "culprit".

    I tried to format it to NTFS file system and assign a drive letter, but nothing work. The window where I had to choose the format would pop up.

    Windows could not complete formatting: the disk was too big and the standard formatting tool is limited.

    Partition your hard disk into several partitions, for different data types (e.g. music, video, documents, etc.), for each drive to specify the file system type. The easiest way to do this is through a disk and partition manager such as Acronis Disk Director.

    “Hello. My name is Kim. I discovered that technology, when used with a purpose, can be pretty amazing. To share the wonder of tech, I’ve written for blogs like and With over three years of freelance writing experience in the technology and entertainment niche, I can write a storm about a software app, a cool browser extension, a new mobile device and other geek-centric stuf... “

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    Kim Barloso