First, make sure that you have the current OS available from Roland. This can be found at their website, rolandus.com

Usually the file is quite large and therefore is compressed by Roland to make downloading easier. The downloaded file is compressed as a .zip file and will need to be unzipped using either WinZip on a Windows PC or StuffIt on a Macintosh.

If you need, you can get WinZip from the following link: winzip.com

If you need, you can get Stuffit Expander from the following link: www.stuffit.com
Now that you have the current OS, here is how to load it correctly:

Insert the disk into the MV-8000
Turn off the MV-8000
Hold down both the Instrument button and the Disk USB button and power the unit up.
The OS should start loading automatically. Once you see activity on the screen you can release the buttons.
After the OS is fully loaded, reboot the MV-8000 and it should be ready to go with a updated operating system.