Just for everyone's knowledge I am experiencing the same issues only in slightly different circumstances. I have been searching for a few days now and I as well can find no definitive answers to the inconsistent recognition and flakey behavior of system and booting once NVMe EVO is installed. I am beginning to believe this is purely a Samsung issue as similar occurrences with other similar MBO and 'disappearing HW' and flakely recognition states abound. My dilema:
Current before M.2 attempts:
ASUS Z170-AR MBO
Samsung EVO 850 SSD 500GB - Boot drive - connected to SATA OS Boot port (1 of 4)
2 Toshiba 4TB Drives - HDD
1 older HDD (forget exact model-disconnected for time being as it was connected to SATA Express and short on ports - part of the reason I went with M.2)
1 BDRE -LG
Corsair Memory
1 GPU - don't have exact model at finger tips but didn't think relevant
Win 7 Ultimate - It all worked wonderfully, very fast boot from SSD, great performance overall.
Then - I wanted to re-purpose the 500Gb 850 to a laptop and thought, hey, i'm going to splurge and get an NVMe and really get great performance and try the latest and greatest. I wish I had just saved the $100 and just bought another 850! All of this to install a new drive is just plain silly and it appears the technology is not ready for prime time yet. I welcome someone to prove me wrong but considering all the posts I have seen with many with all different kinds of systems but yet same strange behavior without definitive answers leads me to my conclusion.
Sorry for the ramble but frustrated obviously.
My plan was: drop in the NVMe, Clone 850, Pull out 850, set BIOS to boot from new NVMe. Done.
After 2 days, I'm still trying to get the 960 recognized by OS so I can clone to it. Magician can't see it.
Shows up in BIOS fine, always has. But in BIOS I am unable to save the option to for M.2 support. Everytime I try to save and go back in, back to SATA Express. (In the Save step, it tell me it is changing the setting?) But now my system will start to boot, then hang. Reboot, gee now it works fine. (boots fine but will not recognize the drive still in OS. Sometimes it doesn't boot after a few attempts, then I need to go into BIOS, do something silly, sometimes just select defaults (which it was already set to) and then it will boot from 850. No reason it should but does. or I specific tell it it boot from 850 even though 1st priority, and that works, nothing else changed. Just weird and inconsistent.
All of this seemed to start, after I tried installing Samsung Driver to get win7 to recognize the drive. But I did do that pretty quickly early on based on one post recommendation elsewhere due to lack of NVMe boot in Win7 Natively.. I can see in BIOS fine. I actually had to let Windows repair the install once to get past the boot hang. I think it removed the new driver but can't be sure. Back to booting intermittently and still no drive recognition by OS.
I don't believe the driver actually installed properly, perhaps confused by the 850 being there as well.
Anyway - don't know about others but I have CONSISTENTLY had issues with anything Samsung and SW/Drivers/whatever. Not purposely bashing Samsung, I have a lot of their stuff everywhere. But this is just par.
Does anyone have any ideas? I am still within my window to return the 960 and seriously considering it.
Magician won't see it unless I follow hugely strange BIOS setting changes, pull other drives, disable other stuff etc etc. I will not start from a scratch install, pull msi and stick on USB as part of that, or do Win10, have my reasons I won't get into but if I have to go down that path, benefits of new faster drive are now gone as far as I am concerned. It really was pretty awesome with 850 already compared to my old system before recent upgrade. ASUS manual? nothing there. just - oh you can't use SATA Express and M.2 at the same time. The depth of their install instructions....
I have read - 'pull out all drives' then try, that usually works - but for clean OS install right? Can it do that and then put all drives back in so I can clone? And it will magically then all work again? (This is my 'not ready for prime time part'...)
Anyway - Just wanted to say 'good luck' and let you know you don't appear to be alone by any means no matter what you are running. Maybe other MBOs are just 'luckier'? (one other poster with MSI seems to be having exact same issues)