Accident run Memtest86 on a usb drive

[puzzled99]

Hi there. I downloaded Memtest86 onto my USB drive and accidentally selected my USB drive to boot my laptop. I stopped the process immediately, but found out that the data in my USB drive have been deleted after I tried to access my USB drive.

Is there a way to recover the lost data with the folder structure on my USB drive? Thank you for your help in advance.

[David (PassMark)]

Booting from a USB drive doesn't delete the content of the USB drive (nor any other drive connected to the system). So it doesn't matter if you booted it up or not.

However if you used ImageUSB to write the MemTest86 USB drive image to your USB drive, then data on the drive will have been overwritten. There are however multiple warning displayed before it does this, so it should be very hard to have an accident.

If you really did ignore the warnings and overwrite your drive, then all the data near the start of the drive is lost. Data near the end of the drive will be untouched, but without the partition information and master file table you'll need to do a forensic recovery of whatever hasn't been overwritten. Maybe you'll get some of them back, with enough time & effort.

[puzzled99]

Booting from a USB drive doesn't delete the content of the USB drive (nor any other drive connected to the system). So it doesn't matter if you booted it up or not.

However if you used ImageUSB to write the MemTest86 USB drive image to your USB drive, then data on the drive will have been overwritten. There are however multiple warning displayed before it does this, so it should be very hard to have an accident.

If you really did ignore the warnings and overwrite your drive, then all the data near the start of the drive is lost. Data near the end of the drive will be untouched, but without the partition information and master file table you'll need to do a forensic recovery of whatever hasn't been overwritten. Maybe you'll get some of them back, with enough time & effort.

Thanks, David. I only booted my laptop from the USB, and after cancelling the boot before it finished and re-logging into my laptop, I found similar issue that others have raised, where the disk space has shrunk from 250 GB to 48.8 MB, and I could no longer see my other old files and folders.

I don't think I have selected the used ImageUSD to write the MemTest86 USB drive immage to my USB drive. I just downloaded the Memtest86 programme, and rebooted my laptop from my USB drive (which I cancelled before it finished). When I logged into my laptop again, I found that the USB drive disk space is already 48.8 MB. Does this mean my files are still in my USB drive, but it is just that I could not see them right now?

Apologies for my fairly basic questions here, as I am not familiar with how this test actually works.

[puzzled99]

I should probably add that the 48.8 MB contains the EFI related files only, which should have been created by Memtest86 after my booting with the USB drive?

[David (PassMark)]

Again, in bold this time. Booting your PC from a USB drive doesn't results in files being deleted.

Copying a file to a USB drive doesn't make the USB drive bootable either. I think you must be confused about what you did. Either the drive was already bootable before you started, or you used ImageUSB to make it bootable.

If the drive is now 48MB, then I think you must have used ImageUSB & ignored the multiple warnings.

It is easy to reformat / re-partition the drive to make the size 250GB again. But reformatting the drive won't recover the lost files.