mac os x unable to unmount volume for repair

You can verify your disk with file command:

gzip -c > .gz : Create compressed disk image using gzip.

bs=64k or bs=1m or bs=512 : Set both input and output block size to n bytes.

$ sudo dd if=/dev/disk2 bs=64K | gzip -c > .gz You can create compressed disk image as follows: You can press the ctrl+ t (hold control key and press t) to see dd command progress on macOS: Password:ģ965190144 bytes transferred in 839.664927 secs (4722348 bytes/sec) It will take some time, and you won’t see any updates on the screen. $ sudo dd if=/dev/disk2 of=backup.my. bs=1m $ sudo dd if=/dev/disk2 of=backup.my. bs=512 Create the disk image with ddįinally create the disk image of the entire disk /dev/disk2:

Here is what we see: Unmount of all volumes on disk2 was successful 3. In this example my SD card size is 4GB and located at /dev/disk2. Open the Terminal application and type the following command to list disks:įig.01: Insert in your SD card, or USB pen/HDD, and see /dev/diskN name To write the disk image: dd if=image.dd of=/dev/DISK.To create the disk image: dd if=/dev/DISK of=image.dd bs=512.How To Create Disk Image on Mac OS X With dd Command Always keep verified backups for your Mac. WARNING: Please be careful when running the following commands, as you might destroy essential data or disk. You also need to use diskutil command manipulates the structure of local disks including listing and unmouting disks before you create or write images to disk. Create new disk images from USB or SD card.

Mac os x unable to unmount volume for repair