Firewire Driver keeps disappearing!

Recently acquired (3) MR816CSX devices and trying to use with Cubase Pro 8.5 and Wavelab 8.5. The Yamaha latest driver (V 1.7.4) for firewire keeps disappearing from BOTH Cubase and Wavelab when i go to launch them! At first, i had to annoyingly go into Device Setup and re-choose the Yamaha driver when it defaulted to Built-In Audio…but NOW, i can’t even choose it any more. So, i tried re-installing and it worked…once. Now in the same boat again.
Am i screwed choosing the CSXs?? I also found out i cannot direct monitor from all 3 devices at the same time using Cubase’s Control Room (which is a GREAT idea) but what’s the point if i can’t direct monitor using control room? Who needs the control room cue sends AFTER tracking??
A Steinberg tech said i’m better off getting a UR824, using that as my main I/O and connecting (2) of my 816csxs via Adat…giving me 24 channels of direct monitoring. BUT, will this allow me to direct monitor using the Control Room in Cubase??
Ugh, any advice on what i should replace to get Cubase and Wavelab working great with 24 channels of direct monitoring so i can give up to 6 people their own headphone mixes using the cue sends in Cubase??? Btw, i am using an Art HeadAmp6 Pro as my headphone amp that i was trying to feed the 6 headphone outs from my (3) 816csxs.

Thank you in advance! (Also, i have been through several forums with not much success)

I had the same, with the 1394 OCHI controller missing from device manager (windows 7 64bit, and x99 chipset on an ASUS x99 motherboard). Installed 2 things a-new, the chipset drivers AND the mother board BIOS. It seems to have helped, the OCHI cotroller is back. PS make sure you choose the Legacy driver, as it works better. -F