Are you unable to access your Mac data? Does your Mac partition failed with error could not unmount disk? Definitely, it's a panic situation for anyone whenever he encounter such very critical issues. Basically, this type of problems appears while partitioning, verifying or repairing disk permission and formatting disk using disk utility. According to professional experts, partition failed with error could not unmount disk arises when there is a modification done in boot drive. So in order to fix Mac partition failed with error could not unmount disk one have to boot the system from other drive and then after run disk utility. For this you may try the following steps:
Resolve unmount disk issue using USB drive
- With Mac, first make attachment of USB boot drive and then after reboot
- holding option key during boot choose attached boot-able drive
- then, select disk utility from boot menu.
- Verify disk moving to the 'First Aid' and repair it if required.
- Lastly, fix could not unmount disk error.
Resolve disk utility error using Recovery Partition.
- Firstly, boot Mac holding 'Option key' along with choosing recovery partition.
- Now select 'Disk Utility' from boot menu.
- Then after move to 'First aid for verifying/repairing disk.
- Now, select erase to format disk.
Going through the very step, hopefully you will solve Mac partition failed with error could not unmount disk. If you have lose data in order to fix the issue need not to worry as using Mac Data Recovery Software you can easily recover your lost data.