Available article translations:

An error occurred while accessing the Hard Disk ...

  • Parallels Desktop for Mac Standard Edition


Parallels Desktop displays the following error message:

Operation failed


An error occurred while accessing the Hard Disk used by "VM_NAME". ... PRL_ERR_DISK_READ_FAILED(820021029),errno=5 (input/output error)



    Error ID: PRL_ERR_DISK_READ_FAILED (80021029), errno=60 (Operation timed out).


  • The Virtual Machine is located on a network drive which is disconnected
  • Mac HD corruption issue
  • Boot Camp virtual machine failure


If your Virtual Machine is on a network driver: make sure it is connected.

If the Virtual Machine in question is located on Mac HD, it is most likely corrupted. You may check it this way:

Launch Console (open Finder, go to Applications -> Utilities ->

  • for Mac OS X Lion and earlier: locate kernel log.

  • for Mac OS X Mountain Lion: locate system.log

Look for "I/O" patterns. You should see that the log contains input/output errors of this kind:

Sep  2 12:59:11 <HOSTNAME> kernel[0]: disk0s2: I/O error.
Sep  2 12:59:25 <HOSTNAME> kernel[0]: disk0s2: I/O error.


  1. Open Terminal application (Finder -> Applications -> Utilities -> Terminal);

  2. Copy the following command, paste it into Terminal window and press Return:

    cp -vR path_to_the_vm /dev/null

In case you will receive any error similar to message below:

     cp: /Volumes/WPro/Virtual Machines.localized/Using/Windows 8.1.pvm/Windows 8.1-0.hdd/Windows 8.1-0.hdd.0.{5fbaabe3-6958-40ff-92a7-860e329aab41}.hds: Input/output error

It means your Virtual Machine is located on corrupted sectors of Macintosh HD and Mac OS X kernel cannot read its data from the drive.

We strongly recommend to show your Mac HD to Apple because bad sectors may indicate a hardware problem and are likely to reappear.

Before you contact Apple support we recommend to follow the steps below that may help to recover your data from the Virtual Machine's hard drive:

1) Locate the .pvm bundle of the Virtual Machine on your Mac HD using Spotlight > right click on the found .pvm file and choose "Show package content";

2) Inside you will see an .hdd file -> right click on it -> open with Parallels Mounter. The virtual machine's hard drive will be mounted to your file system and should appear in Finder;

3) If a new drive appeared in Finder, open it and copy folders that you need to Mac HD step-by-step (not all folders at once).

Note: At this step some folders may fail to be copied. It means that they or their contents were corrupted. If you meet such a folder, open it and try to copy its contents the same way, step-by-step.

4) If no new drives appeared in Finder, it means the virtual machine's critical part was corrupted and there is no way to retrieve data from it using Parallels applications.

Note: Regardless of a troubleshooting outcome the issue is not Parallels Desktop related and there are no further steps to be taken from the Parallels side.

If the virtual machine is installed from Boot Camp partition:

  1. Locate your Boot Camp virtual machine .pvm file in Spotlight and move it to trash.
  2. Reinstall the Virtual machine from Boot Camp partition via Parallels Desktop upper menu -> File... -> New.

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