diskpart in WinPE (from CMD Shift+F10) - delay start 10-15 sec

When I run diskpart 64-bit in WinPE, the cursor _ flashes for about 10-15 seconds before the appearance of DISKPART>
It is only at the first launch after the start of WinPE. If we leave diskpart through exit and run again, it starts in ~3 seconds

Tested on VMware Workstation 8 HW8, virtual HDD IDE, UEFI mode:
Part of .vmx settings:

Code:

ide0:0.present = "TRUE"
ide0:0.fileName = "Windows 7 x64 UEFI.vmdk"

guestOS = "windows7-64"

firmware = "efi"

The same problem is with diskpart 32-bit on MS Virtual PC 2007

Tested other PC with NVMe disk and diskpart run ~3 seconds