I'm having the exact same problem.
Played the game a few days ago (on my WD Caviar Black) and all seemed okay
Got a 1Tb Samsung 840 Evo in the mail today, everything works perfectly but when I started Blade & Soul it gave me an update. Installed it, started the game, 'explorer.exe' starts acting weird (desktop icons disappear), few seconds later I am faced with the bluescreen (Critical_process_died) with a percentage bar that doesn't move from "0%".
What I've tried so far:
- Re-installing Nvidia drivers (trying v376.33 as well as v378.49) for my GTX 1070
- Uninstalling NCSoft Launcher and manually removing every trace from NCSoft from my drives, appdata and registry
- Check other drivers (no outdated ones found)
- Reinstalling Blade and Soul (with the NCSoft Launcher of course), waited 2 hours for the download to complete (but no luck this time either)
- Checked my Windows installation via "sfc /scannow" and "/DISM [...], no errors found on other disks either (SMART data is 100% 'GOOD')
All of the above in no particular order.
OS: Windows 10 Home x64
Configuration: 250Gb Boot drive, installed Blade & Soul on my new SSD (1Tb D-drive). My WD Black used to be secondary, I cloned the Black on the SSD and now the 840 is my D:\")
All I've been doing for the last 3 or so hours is trying to solve this Blade&Soul bluescreen-issue, Googling "Blade and soul critical process died" didn't yield any (useful) results. However, only now at 02:15 in the morning I found this thread by replacing the words "critical process died" to a less specific "Blade and soul bluescreen". I'm somewhat glad to see I'm not the only one, thanks to you all for trying to help resolve it.