I'll add to what lampdog said and remind you:
- If using removable storage for sample data and project storage, etc, - such an SD Card or USB Stick/drive, make sure you soft "eject" the media BEFORE you remove it from your MPC X, or before going from Controller Mode to standalone mode when connected to your computer. Failure to do so will end up corrupting your media over time. If you install a SATA drive for storage, make sure you soft "eject" it via your computer OS when switching from Controller Mode to standalone for the same reason.
- I bears repeating: do NOT tamper with any data on the built-in storage. You will inevitably cause problems for yourself down the line.
- Strongly encourage you to consider mounting an SSD into the internal SATA cradle and use that as your main Expansion storage, sample/Project storage, etc. They're super cheap these days and will be one less thing to lose.
Enjoy!