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    Technology Manager of Test Dept.

You may lose data in SD card or PC require you to format it before using. However, when you confirm, you receive that “Windows was unable to complete the format”. What is it and how to solve? All possible reasons and solution could be found here.

It is common for us to use SD card in Android phone and digital camera to save data. However, SD will lose data inside. Sometimes we may meet worse situation: the portable devices can not recognize the SD card and computer notifies that the SD card need to be format. Usually, we can use the SD card again after format.However, sometimes you may receive the notifications like the following:
how if sd card cannot be formatted

Solution for SD Card can not Format

Usually, if we receive the notification from Windows that the SD card can not format, it means that the controller of the SD card gets into big trouble or it is nearly to be dead. (The controller of the SD card stops all data writing operation but allow the data access operation.)
No matter which situation we meet, solution is the same:
1. Recover Important Data in SD Card ASAP
We can not get access to data inside the SD card since Windows requires to format the SD card. Then we need to use the data recovery software to recover data inside before all data lost.
If you want to find a freeware, we recommend you to try Photorec which can scan and recover lost files. However, its interface is hard to understand.
use ph
Then you can try another data recovery software – Renee Undeleter which can scan whole disk and preview the scanned lost files when scanning process. Also, it can scan whole disk to find lost files. This helps users to confirm the quality of the recovered files.
Hot Topic - ADsRenee Undeleter – Save Data from Unrecognizable/Unreadable Devices

Strong to recover Recover data from the storage devices sustaining many bad sectors;

Supported devices SD card, SDHC, SDXC, USB flash drive, hard disk and computer;

Supported file types Image, video, audio, text, email and so on;

Easy to use Recover data by 3 steps and support to preview scan results;

Multiple scan modes Fast partition/whole partition/whole disk scan.

Easy to use Recover data by 3 steps;

Multiple scan modes Fast partition/whole partition/whole disk scan;

Supported devices SD card/USB/hard disk, etc.

Free TrialFree TrialFree Trial 800 people have downloaded!
Preparation: Download and install Renee Undeleter.
press to the download button
download button mac5
Step 1: Launch Renee Undeleter and select “Whole Partition Recovery”.
select whole partition scan in renee undeleter
Step 2: Select the target SD card and click “Next” to process the scan.
select target disk to process scan
Step 3: When the software scan, you can preview the files in the scan result.
preview before recovery
Although Renee Undeleter is a shareware, it has 20MB free recovery quota (Click here for more information). We recommend users can make use of this 20MB to ensure the recovery of important files. And after that, you can recover other files with freeware – Photorec.
If the data recovery software can not detect any information of the SD card, please format the SD card with low-level formatting software in Part 2.
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2. Repair the SD Card with Low-level Formatting Tools after Recovery
Reasons why some SD card can not format is that users may eject the SD card when it still saving data. And the controller did not save some control information to the flash memory in time. Lacking of such important information, controller of the SD card can not work normally. As a result, portable devices even Windows can not save data to SD card.
We need to reset all information in the SD card with some low-level formatting tools to solve this problem.

Attention: All lost files and data will not be able to recover after low-level formatting.

Structure of SD card
sd card structure
Here, we recommend SD Memory Card Formatter. (Click here to download the software.) Parts of SD card can use normally after low-level formatting.
windows was unable to complete the format with sd card formatter
formatting memory card
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3. Exchange the SD Card in Store If SD Card Does Not Work after Low-level Formatting
SD card purchased in a formal way will get 3-5 years guarantee. If you meet quality problem like it can not be recognized or can not use, you can exchange the SD card in store.
Contact information of Main stream SD card manufacturers:
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Reasons for SD Card can not Format and Even Unrecoverable

Firstly, we need to get more about the flash memory chips of the SD card. Flash memory chip in popular SD cards is TLC. It is rare that SD card is with MLC flash memory chip. And some SD card for military usage is with SLC flash memory chip. We can get a general comparison among the 3 different flash memory types from the following chart:

NAND Flash

SLC - Single Level Cell

MLC - Multi-Level Cell

TLC - Triple Level Cell

Read/Write Cycles90,000-100,0008,000-10,000500-1000
Bit Per Cell123
Write Speed★★★★★★★★☆☆★★☆☆☆
From number of read/write cycles, we can know that SD card with TLC flash memory chip can read/write for 500-1000 times. But what does it mean?
It means each storage cell can save data for 500 times. And controller will stops the data saving operation to the cell once it reach the limitation. And users can only read data inside. This is the reason why you receive notification from Windows that you need to format the SD card or it can not be format. So, we have to recover important data from the SD card at first.

If the read/write cycles of TLC is 500 times, how long can we use the SD card? If you save files to SD card for 1-2 times, files system of the SD card will be modified 3-4 times per day. The life of the SD card will last for about 250 days. However, if the quality of flash memory in SD card is poor, the life of the SD card will be shorter.

You may confuse here. 500 read/write cycles is for single cell. Data saving in the SD card will not save in the same cell. The life of the SD card should be longer. However, SD card is different from HDD. If one cell fails, whole SD card fails. Writing data to SD card will change the information in the file system for 1-2 times at least. Once this information saving cell reach the read/write cycles, whole SD card will fail to work and users can only read data inside. Some even can not be recognized.

Besides, the size of SD card is tiny and can not use the controller chips with the effective asymptotical algorithm of load balance. This algorithm make a longer life of SSD with same TLC flash memory in SD card.

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Recommendation for SD Card in Mobile and Digital Cameras

If you use SD card in your Android phonefor storage devices, we recommend you to backup data inside the SD card each 1 or 2 months.
Attention:Please do not make the SD card save cache of Android phones. This will greatly shorten the life span of the SD card. Maybe in one week you need to purchase a new SD card for your Android phone.
If you use SD card in your digital camera, we recommend you to export the photos and videos in SD card to PC as soon as possible.
Although using SD card gets great convenience, it is easy to get damage and lead to data lost. Here, we recommend you to backup or clone data in SD card regularly with professional data backup software – Renee Becca. Click Free SD Card Backup and Restore for more information.
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