COULDNT UNMOUNT DISK MAC OS PASSWORD

Open the Terminal utility (Applications > Utilities) and enter “root” mode by running the following command (supply your password when prompted-it will not be shown):.

With this effort, the hope is to bypass the corrupted drive logic that is causing the system to hang up when accessing it, but since the drive is captured by the system and held in a “busy” state whenever attached, doing this may require using Terminal commands in special timing: This will destroy any partitioning schemes and current formatting, and make the drive appear to the system as a blank storage device.

COULDNT UNMOUNT DISK MAC OS GENERATOR

If you have a local storage drive that is malfunctioning, and especially because of a low-level formatting issue, then you can use the random number generator device to force overwriting of the hard disk. You can see this by running the following command in the terminal to read through the “random” device file (be ready to press Control-C to stop the torrent of characters that will be output from this command): cat /dev/random When /dev/random is accessed and read, it will output random data. For /dev/null, this device acts like an instant trash can for any information sent to it, and is useful for scripting and programming. In Unix-based systems like OS X, often there are some special device drivers, such as /dev/null, or /dev/random, which instead of providing access to system devices, offer unique services. These allow programs to interact directly with the device, so for instance you can use a filesystem manager like the “diskutil” command to get information on, or fix a device.įor local storage drives, your boot drive is the first enumerated disk device, so it will be assigned the device file /dev/disk0, and you can get information on it in the Terminal by running the following “diskutil” command: diskutil info /dev/disk1

COULDNT UNMOUNT DISK MAC OS DRIVERS

These devices include disks, consoles, terminals, and standard input and output, among others (click for larger view).ĭevice files in OS X are a collection of drivers in the hidden “/dev” directory that are assigned to devices, allowing them to be accessed by system calls (open, read, write, close, etc.).

The /dev folder has a number of different device files that are assigned to system components and peripherals, allowing programs to interact with them using system calls.

COULDNT UNMOUNT DISK MAC OS HOW TO

This is especially true if you do not hear any tell-tale signs of physical failure, such as repeated click, tap, and whirr sounds coming from the drive at regular intervals.Īssuming the drive is just experiencing major low-level corruption, the problem you face now is how to format a drive that apparently cannot be formatted on your Mac? One option is to use another operating system like Windows in Boot Camp, in a Virtual Machine, or on a dedicated PC to manage the drive and attempt to repartition it however, this may not be feasible in some situations.Īnother option that should work in most cases is to use the Terminal to interact with special device files to force an overwrite of the device file representing the drive. These errors and behaviors might indicate to you that your drive is malfunctioning and you need a new one however, before you give up on a $100+ drive, ensure the problem is not simply a very low-level formatting snag that causes the drive to hang when accessed. Another possible symptom is if you get this error or one claiming the drive cannot be unmounted, when trying to format the drive or running a fix routine on it with Disk Utility. If this happens, the drive may show up in the Finder sidebar but not show data when clicked, or it may just not show up but be present in Disk Utility however, if you try to mount it you get a “resource busy” error.

Even though formatting advances like Journaling in Apple’s filesystem formats help prevent data corruption, problems can still happen that result in a drive not only being unreadable, but also unable to be reformatted.

Couldnt unmount disk mac os