When is WinRE Partition created on Windows 10 upgrade?

Question

When we upgrade Windows 8.1 systems (UEFI) to Windows 10, we see a 450 MB Recovery Partition is created from the OS partition.
On searching further, we figured this is the new WinRE partition created by the Windows 10 upgrade process.

However, we dont see this issue all the times and only on some systems.
Under what conditions is this WinRE partition created during Windows 10 upgrade?
Is there any configuration parameter we can specify which disables this behaviour?

Answer 1

I was able to disable this behaviour using the "/resizerecoverypartition disable" switch at the commandline for the Windows 10 Setup executable.