Try unRAIDing the caching SSD so that it goes inert until it gets it's driver and later can be re-enabled. You may need to read your Manual on the PC's Support Downloads webpage to find out exactly how. Some have a RAID controller pop-up at boot, others are adjusted in BIOS setup under SATA controller settings - change from RAID to AHCI to try install.
If this is the 32gb SSD caching chip it is cut loose and even available for OS install by unRAIDing and turning off Hardware Acceleration in the Intel control panel. Read the Manual for more specific instructions.