I am trying to format an SD card and an USB flash drive. When I use the Disk Utility application I receive the following message: "Couldn't open device" I also tried via terminal and the message I get is "-69877: Couldn't open device" If I try to repartition the drives I get the same message.

Please note that those usb flash drives and SD cards work fine in Parallels/Windows7 setup.

1 Answer 1


This may be a problem with Disk Utility.app and diskutil. I would recommend booting into recovery mode (CMD + R at startup) and verifying the main hard disk. If this turns up fine then a reinstall or restoring from a backup where the problem did not take place is the way to go.

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