Sometimes we just mistakenly hit the Format button or don’t properly format an SD Card after getting the message “You need to format the disk in drive XXX before you can use it.”, and then we lost all important files stored on the SD Card, like family photos, confidential documents, precious videos, etc. There is no function to directly reverse or undo the SD Card formatting, but we can still unformat an SD Card by recovering data from formatted SD card with tools.
Now, let’s see how to unformat SD card on computer and Android phone, and there is freeware available for this task.
Best Data Recovery for Windows and Mac
Free Download Windows 11/10/8/7
Free Download macOS 10.9 or later
Yes. Surely you can unformat an SD card by specific data recovery tools if acting quickly.
Most people think formatting an SD card would remove all the files stored on it instantly. Actually, the fact is that they won’t disappear immediately, as formatting process just restores your memory card to default setting and marks it as blank.
In other words, after formatting, your SD Card will write the boot sector and the empty file system to partitions. Then the card will be filled with new data until all previous formatted files are overwritten. Your files haven’t yet been completely deleted and you still have a chance to unformat SD card. Any operations done to your SD card might overwrite the existing data, which gives rise to permanent data loss. Therefore, before unformatting SD card, stop using it right now!
Here we will recommend 3 ways altogether to unformat SD Card on computer. You can choose the one meeting your needs the most.
With the assistance of Cisdem Data Recovery for Windows and Mac, you can carry on SD card unformatting yourself on a computer, without asking an expert. As the best unformat memory card software, Cisdem can recover deleted, lost, formatted or corrupted files from internal and external hard disk, SD card, USB flash drive, digital camera, game console, whatever be the device that connect to your computer machine.
It offers quick and deep data recovery modes dedicated to different data loss scenarios: deletion, formatting, partition loss, repartition, virus attack, system crash, etc. Cisdem also allows to preview recoverable items before recovery, saving your time and space not to recover unwanted files.
Free Download Windows 11/10/8/7 Free Download macOS 10.9 or later 
In addition to Cisdem Data Recovery, another 2 pieces of freeware will be also introduced as following. What calls for your attention is that the coming apps are not guaranteed to be 100% working on your Mac or Windows, but are still worth a try if you want to undo the format on your SD memory card and get the formatted files back for free.
Recuva is a Windows program famous for performing well in recovering files lost due to format or deletion. In addition to SD card, it’s also capable of restoring files from internal hard drive and removable media such as flash drive, USB, floppy disk, etc. It’s available in both free and paid version, but the free version is more than enough to unformat an SD card and recover files from the formatted memory card.
Insert your SD card into PC via a card reader.
Download and install Recuva.
Open it > select the file type you want to recover > click Next.
Click Browse to select your formatted SD card to scan.
In the next Recuva Wizard window, enable Deep Scan > click Start.
Wait for Recuva to scan the card. Choose the desired files and click Recover to unformat an SD card.
PhotoRec is an open source application developed for recovering lost files from hard disks, memory cards, CD-ROM. Though PhotoRec uses read-only principle to read the drive and card which makes it safe to use, it uses commands to recover files, so users will have to use the arrows keys to make options when specific commands run in Terminal app. It is not user-friendly, but useful to unformat SD card on Mac free.
On Android phones, you can directly unformat an SD Card without computer, at the aid of an Android SD Card recovery application. There are many options available online, we have tested several high-ranking apps and now pick out the best one for you: Photo/Video Recovery developed by Daniel Braga.
This program can be used freely to undelete various files from both Android SD Card and internal storage. No rooting will be required and your files are still safe on your Android phone. This is how to unformat SD card as internal storage or external source on Android phone.
Mistaken or improper SD card formatting could always result in file missing. Luckily, with useful tools like Cisdem Data Recovery for Mac or Windows, you are able to unformat your SD Card and recover lost files in an easy and quick manner. Moreover, backup is always the best solution for all kinds of data loss. We should keep a good habit of backup by copying important files from SD card to multi-devices, even to cloud services.
Connie has been writing for Mac productivity and utility apps since 2009. Each review and solution is based on her practical tests, she is aways energetic and trustworthy in this field.
Thomas
Editor, can you please provide more details of the method 2# Using PhotoRec? Now I'm having some trouble in the recovery process...