Bootcamp using chkdsk /b flags free space as bad sectors

MacBook Pro (2016) with 256GB SSD, 150GB for Bootcamp. Ran chkdsk /b as recommended before saving Winclone 6 image. About 90% of Bootcamp partition is now flagged with bad sectors. Rerunning chkdsk /b is no help. Neither are MacOS disk tools.

Sounds like you are having disk errors and I would proceed cautiously. You may need to replace the drive.


I have this problem as well. It’s a brand new computer and Apple’s Disk Utility says the disk is fine.

Does chkdsk give the errors or Winclone?


Chkdsk /b runs until it hangs and the machine reboots automatically. When I check the Windows partition after that, there is almost no remaining free space.

After this happened the first time, I wiped the partition in Disk Utility and restored from a Winclone backup. Then I ran chkdsk with the same space-gobbling result.

After wiping the partition again and restoring, Windows is now running fine. Somehow, however, the amount of space used on the partition is unreasonably large, about twice the size of the Winclone backup.

Has this issue ever been resolved?

I’ve just restored a Bootcamp image from an iMac onto my brandnew MacBook Pro 16 with a 2TB SSD. Half of the sectors of the restored Bootcamp partition are flagged as bad. I tried several different chkdsk repairs without making a dent. How is this possible?

I’m having the same issue on my new MacBook Pro 16. I suspect that this issue is caused by the AppleSSD.sys driver. After booting from a Windows 10 installation USB stick into a recovery console (using Shift+F10), I formatted the BootCamp partition with NTFS. At first, “chkdsk /f” does not report any errors. But running “chkdsk /r” converted ALL sectors of the entire partion to bad sectors. “0 KB available”. So, there you go.

My best guess is that we have to wait for Apple to update the SSD driver in order to fix this issue.