Mystery partitions with dynamic disk RAID 1

Question

I have mystery hidden partitions at the beginning and end of the hard drives in my Windows RAID 1 volume and I am trying to find out what their purpose is.

Here is the scenario -

Before installing Windows 8.1, I hooked up one of the drives to another computer so I could partition the entire drive (to prevent a system reserved partition from being created when installing Windows). After I partitioned the drive to use all available space, I hooked it up to this computer and installed Windows 8.1 x64 (non-GPT).

I then ran diskpart inside Windows and confirmed it only had 1 partition of 465gb (however with an offset of 1024kb which I thought was odd). I then converted to dynamic disk and set up a RAID 1 with another disk partitioned in exactly the same way. Now when I run diskpart, it shows 3 partitions

All partitions are now marked hidden, and notice how my 465gb partition is now partition 2. Partitions 1 and 3 are not associated with any volume apparently. I think the last partition may be the dynamic disk LDM database, but what is the first?

This hidden first partition is causing problems when I try to use specific disk encryption software. Is there any way to create a Windows RAID 1 without this hidden first partition?

Thanks for taking the time to read this :)

Answer 1

When you're encrypting your system, Windows needs a boot partition. It can't boot from an encrypted partition. It needs something to startup the tool that unencrypts the encrypted partition, after which Windows can load. I can't tell if this is the case, but it might very well be.