Maybe it will help to somebody. The steps I made to fix it: 1. Delete virtual disk 2. Delete RAID 3. Create RAID again 4. Slow inicialization 5. OS installation
Hello guys, Few weeks ago I have installed R640 server with ESXi 6.0.0 through pxe. It was installed successfully. I would like to reinstall the same server but somehow pxe boot doesn't work. It is looking for mac address but it didn't receive anything from dhcp. The strange thing is that I am able to install new host with the same way with the same dhcp, with the same image in the same network...But if I am trying to reinstall already installed host it doesn't work. If I will block C drive where ESXi 6.0.0 is installed in BIOS and I will keep just network card there it will work. But it can't install OS because C drive is disabled from Bios. Is there anything in the BIOS which is blocking it? Thank you. I have the newest versions of idrac and bios installed.  
PowerEdge R640 pxe boot re-installation