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SD card, a new flash memory made of semi-conductor, features small size, quick transmission and hot pluggability. Though it is widely used in portable devices, you may not clearly know how to use it. What is different between low level format and high level format? How to format SD cards in different types? How to recover formatted SD card?

Part 1. What is SD Card Formatting?
In the operating system, the file system controls how data is stored and retrieved, in charge of allocating space. That is to say, the file system creates, saves, draws and transfer files and withdraws unused files.

Creating file system is also called as formatting or high-level formatting. It will initialize disks or partitions where all files will be erased.

Part 2. How about SD Card File Systems?
Here are some common file systems in Windows and MacOS.


By default, FAT is FAT32. It is supported by almost all operating systems, thus it is the ideal file system of disks and SD cards. Yet, when data is being written in the SD card, it cannot integrate all segments beforehand, which will decentralize data and slow down reading/writing data.
1. Default system format

2. Well compatibility

1. Cannot copy a file over 4GB. Generate many file segments

2. Poor security

3. Waste storage space

4. Only support the file name within 8 characters


NTFS is an advanced file system protecting files and directory data. On this basis, it saves storage space and reduces capacity consumption. Compared with FAT, NTFS is improved for higher security, better compression efficiency and faster running. Besides, it supports to compress sparse files and allocate disk quotas.
1. Easy-to-go file management

2. Can copy a file over 4GB and will not generate so many file segments

1. Hard to be recognized by some devices, except computers

2. Cause loss for flash memory


exFAT is the file system for flash memory. Compared with FAT, it is improved for the interoperability between desktop and portable devices, with better performance of the free space allocation.
1. Embrace merits of FAT32 and NTFS

2. Especially suitable for flash memory

1. Incompatible with the earlier devices

2. Need patch files in Windows XP

Differences among FAT, NTFS and exFAT


1. Generally, FAT32 is suggested because of the well compatibility.

2. exFAT can be accepted in the versions above Windows XP.

3. Though exFAT cannot be used in some operating systems, it can utilize storage space as much as possible.

4. NTFS is not suitable for USB.

File systemFAT32NTFSexFAT
Operating systemVersions above Win 95 OSR2Versions above Windows 2000Windows CE 6 / Vista SP1 / Windows 8
Mini. sector512 bytes512 bytes512 bytes
Max. sector64 KB64 KB32768 KB
Max. per file size2 bytes – 4 GBMax. segmented capacity16EB (theoretical value)
Max. formatted capacity2TB (32GB in NT-based operating system)2TB-256TB (larger in GPT partition format)16EB (up to 256T now)


APFS is a file system developed by Apple Inc. as a replacement for HFS+. The core design is encryption. That is to say, every Apple product can share with the secure scheme.
Part 3. How to Format SD Card?
There are different fronts in high-level formatting, including procedures in different operating systems, formatting results and track divisions. In the followings, we talk about how to format SD card in Windows, MacOS and Android.

How to format SD card in Windows?

1. Press the keys [Win + X] to select [Computer Management]. Then in the following screen, click [Disk Management] at the left side.
select disk management in windows
2. Right-click at the target volume to select [Format].
right click to select format sd card in disk management
3. In the pop-up window, select desired file system in [File system]. Then, click [OK].
select file system in sd card formatting if sd card is unexpectedly removed

How to format SD card in MacOS?

1. Click [Go] to select [Utilities] > [Disk Utility].
go to utilities on mac
Encrypt USB Drive in Mac OS open disk utility in macos
2. In the left sidebar, select the target disk and click [Erase] at the top.
erase hard disk drive when it is not showing up in mac
3. Select one in [File system], then click [Erase].
how to format usb or sd card on mac

How to Format SD Card in Android?

1. Go to [Settings] > [Storage].
touch storage on android phone settings
2. Touch [Format SD card].
how to format sd card on Android phone by steps
Part 4. How to Recover Formatted SD Card?
Renee Undeleter is a powerful application of SD card recovery. It supports to recover many file types, including formatted disks. If you want to recover the formatted SD card, it can really help you.

In Renee Undeleter, there are three scan modes, fast partition scan, whole partition scan and whole disk scan. Meanwhile, it is so clear, easy that a newbie can complete all operations.

Renee Undeleter - Powerful Data Recovery SoftwareRenee Undeleter data Recovery software

Easy to use Only simple steps to recover data from storage devices.

Multiple scan modes Fast partition scan, whole partition scan and whole disk scan for different recovery needs.

File types Support to recover pictures, videos, audios, documents, mails, etc.

Supported storage devices Recover data from recycle bin, SD card, external disk, etc.

Supported systems Windows 10, 8.1, 8, 7, Vista, XP, 2000 and Mac OS X10.6, 10.7, 10.8.

Easy to use Only simple steps to recover data from storage devices.

Multiple scan modes - 3 scan modes for different recovery needs.

Supported storage devices Recover data from recycle bin, SD card, external disk, etc.

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3000 users have downloaded Renee Undeleter and found data back!

1. Open Renee Undeleter and select one scan mode. Here we select [Fast Partition Scan].
select whole partition scan in renee undeleter
2. Select the partition of the target SD card, and then click [Next].
Renee Undeleter Whole Partition Scan
3. Wait for scanning. If the SD card is in larger size, it will take a longer time to be scanned. After that, click [Recover] to get the target files.
scan and preview files to recover
Part 5. What is Low Level Formatting?
Low-level formatting is the process of emptying the disk and outlining the sectors to restore the default settings. It can be completed in DOS, Windows NT and Linux, even by the written commands. However, low-level formatting, the operation with physical loss, works for the whole disk. Once it works, all data, including those protected data, will be deleted. Thus, it is not suggested to use low-level formatting unless it is absolutely necessary.

For HDD, low-level formatting can outline the sectors again to avoid the aging or damaged storage blocks. What’s more, this method is also suitable to repair the bad tracks caused by collisions.

For SSD, USB or SD card, low-level formatting (also called as “production”) means refreshing the information of data saving and controling chip, including the storage capacity, chip vendor, the internal storage algorithm, the storage blocks and the list of sectors.

However, some SD cards are unable to be formatted if it is plugged out suddenly when data is being written. This operation will stop the control chip to set the control information into the storage blocks, subsequently leading the SD card not to work. To solve this problem, we can reset the file data and the control information by low-level formatting.

1. Differences between Low Level Formatting and High Level Formatting

1. High-level formatting can be completed by the operating system while low-level formatting should be processed in the control chip by the professional application.

2. The whole disk will be initialized through low-level formatting, while high-level formatting can be done on a target partition.

3. It is impossible to retrieve data after low-level formatting; while the data may be recovered if it is emptied through quick format or full format, parts of high-level formatting.

For example, errors always happen in saving data, and these errors even break down the operation system. Then, you can try low-level formatting. Another example, the parameter (i.e. hard disk interval coefficient) related to low-level formatting is attacked by virus, low-level formatting can help you rebuild it.

2. Merits and Demerits of Low Level Formatting

Merits: First, low-level formatting can lock the blocks damaged by collisions. Second, since low-level formatting can recode and clear all tracks and sectors of the hard disk where the information can be written, it may fix the hard disk.

Demerits: Low-level formatting will empty all data on the hard disk, so users should save or transfer the data beforehand. Besides, it will reduce the hard disk’ lifespan. Be cautious if your hard disk works over 20,000 hours. Low-level formatting may cash the disk if there are too many bad tracks (both physical and logical).

Part 6. Extension
Apart from the above points, low-level formatting is also related to USB production and data security. Next, we will talk about their relationship and the reasons why the SD card is not readable.

1. USB Production Tool and Low-level Formatting

Modifying the USB vendor information or the USB display size is to reset the control chip, which can fix the errors of the control chip, such as USB not recognized, not read or not written.

The control chips differ from the USB brands. You should know which control chip the USB is using, and then you are able to use the right production tool. Note: there are many versions for each control chip. Be patient to try them.

2. Data Security and Low Level Formatting

In fact, high-level formatting is not the process of emptying all data from the hard disk but the way to mark the occupied sectors as “deleted”. After that, the operating system will recognize these sectors as writable. In other words, the data deleted through high-level formatting is never covered by the new data and can be recovered.

On the contrary, low-level formatting will replace each sector with “00”. The data will be totally erased and cannot be recovered.

3. SD Card is not Readable

The followings can lead the SD card fails to read/write data:

① The contacts of the SD card is not clean
If there is ash or stain on the SD card contacts, you can use a piece of alcohol pad to gently clean them. As it is dry, insert it again.

② The battery voltage of phone or mobile device is not stable
The high-quality SD card is hard on the power of phone or mobile device when reading or writing data. The device with a non-original battery probably cannot read the SD card. Please try to use the original battery.

③ The SD card slot is squeezed
Some people like to use the non-original battery. If the battery is thick, it will squeeze the SD card slot, which makes the SD card hard to be read. Please change another suitable battery.

④ The internal mental structure is rusty or excessively bent
If you frequently plug the SD card in and out, the mental structure of the slot will be bent excessively or rusty. Check the structure under sunshine whether it is like this situation. If so, try to use a pin to slightly bend the slot back.

⑤ The SD card is attacked by virus
If the virus is scanned out in the SD card, you can format it to be FAT file system.

⑥ The SD card is formatted improperly
If you don’t follow the routine way to format the SD card, it will be not readable. Please follow the proper way and format it to be FAT file system again on the computer.