Question: My laptop comes with a 128GB SSD, and it have Windows installed. But since it has almost no space, I installed Ubuntu 16.04 on a USB drive (32GB, USB 2.0).

It's working really well, but I don't want that anything goes wrong with my Windows drive, so I modified the `fstab` file and I added 2 lines:

```
UUID=3E98352E9834E655  /mnt/hiro  ntfs  noauto,umask=222  0 0
UUID=24F62FADF62F7E64  /mnt/hiro  ntfs  noauto,umask=222  0 0

```

If I read correcly, those 2 commands disable the mount of those 2 devices (both that Windows uses) and also disable the graphical icon to mount then.

Is this enough to prevent any problem? Or I'm wrong about these 2 commands?

Thank you.

Answer: 
Mounting your Windows filesystems read-only seems a little more straight-forward to me than the umask option:

```
UUID=3E98352E9834E655  /mnt/hiro1  ntfs  ro,noauto  0 0
UUID=24F62FADF62F7E64  /mnt/hiro2  ntfs  ro,noauto  0 0

```

I also made separate mount-points for each filesystem, in case you ever wanted to have them both mounted at the same time
After you've installed Ubuntu, it will never do anything to modify those Windows drives unless you explicitly tell it to.  

In reality, I would never even worry about modifying your fstab file, but keeping the 'noauto' flag won't hurt anything and will, in fact, prevent Ubuntu from trying to mount the drives automatically (just in case, I suppose)