Repairing The Unmountable Boot Volume Error

What does Unmountable Boot Volume mean?

An unmountable boot volume error is quite a common error that people see when they start up their computer and it is usually accompanied by the following.

- A blue screen with an error code
- Rebooting does not fix the problem
- Unable to start the computer in any mode (including safe mode)

Unfortunately the error is caused by data corruption either on the file system or the corruption is due to a bad hard drive (A more serious problem). A lot of techs and forums will tell you that you have no other option than to format your hard drive. Now while this could be the case it is not always necessary in the case of file corruption and in the case of a bad hard drive it is unlikely to fix the problem anyway.

So lets look at the 2 causes and how you can hopefully repair the problem if the cause is due to file corruption.

File Corruption

This is the less serious of the two if this is what is causing the unmountable boot volume error as the chances are you data is recoverable. Even if you do need to reformat the drive you should be able to recover your data first if you drive is just suffering from file corruption. To try and fix the error that is caused by file corruption you do need a few things.

• Your operating system disk or reinstallation disk that came with your computer(Windows 7, Vista, XP)
• Administrator access

Windows 7/Vista

1. Boot your computer from your operating system disk. You can normally select the the boot device by pressing F12 or F9 on your keyboard if the DVD drive is not set as the first boot device.
2. After the welcome screen you should see an option to“Repair my computer” at the bottom of the screen. Select that option.
3. You should then be presented with a number of options and one of them should be command prompt. Select it.
4. In the command prompt type the following chkdsk /rfollowed by your drive letter For example if you drive is D type chkdsk /r D: (On the previous screen under choose a recovery tool your drive may be listed if you are unsure)
5. This will perform a check on your disk for bad sectors and attempt to repair them. If the chkdsk fails to run at all it could be an indication that the hard drive has failed more severely.
6. Reboot the computer once check disk has run (this could take anywhere from 30 minutes to 2 hours)
7. If you still get the same error repeat steps 1 -3 and then this time in the command prompt type bootrec /fixboot This rewrites the master boot record on the hard drive to fix any damaged files.
8. Reboot the computer and hopefully the “unmountable boot volume error” you have been getting should be resolved.

Windows XP

1. Insert your Windows XP CD and boot from the CD
2. Once the files have finished loading press R to enter the repair console
3. You may be required to login
4. Once into the command prompt type chkdsk /p  and press enter. This will check the disk for errors and may take between 30 minutes and two hours.
5. Once check disk has finished checking the disc type fixboot into the command prompt to replace and repair any damaged files
6. Reboot and hopefully you should have resolved the issue.

Hard Drive Failure

Unfortunately if you get the unmountable boot volume error and check disk does not work then the chances are that there is a problem with your hard drive. There are a number of methods you can try to “remap” the hard drive but it is usually my recommendation after recovering the data that you replace the Hard Drive as it does tend to be a recurring problem once it has happened once.

There are varying degrees to hard drive corruption that can cause the unmountable boot volume error from bad sectors to complete hard drive failure where data is only recoverable via expensive Data Recovery specialists.