Since I couldn't find a workaround for this I have decided to disconnect all the RAID 5 SAS drives and perform clean installation while only the SSD drives intended for the OS installation are connected . This step forced windows installer to install the reserved partition on the OS partition and now I should be able to configure the other drives as RAID 5 ( I didn't configure them yet but it should work ) .    Thx . 
Hi everyone .    I have PowerEdge R740.  I have created RAID 5 with Hot spare ( 13 drives with additional one as hot spare) . I did it using Life Cycle DELL 's tool .  I have another set of drives configured as RAID 1 for the OS . I installed Windows server 2019 there . However I can't see any RAID 5 configuration available . All I have is 2 unallocated partitions . One consists on 13 drives and another is the hot spare I have created . I can't even choose anything from the drop down menu . What am I missing here ?  All the drives (Both RAID 1+5) are available on Perc H730 RAID controller .  What can be dome to solve it ?  Thx . 
RAID 5 doesn't show up on windows server 2019