I've been running my FF 400 for years pretty much flawlessly. : ) (At least that I can tell). Recently the FF seemed like maybe it wasn't getting along with win 10 anymore, since the dawn of 1903, due to a number of ongoing BSOD's. I determined that these were caused by the most current win 10 Firewire driver, and remedied the BSOD's by digging up a legacy Firewire driver. Swapping fw cards or cables made no difference. Could not roll back to 1809 at this time.

Concurrent with that problem that I solved, is also the following -

While TotalMix seems to work fine for recording etc (which is great) - also since 1903, I have starting having an error specific to TotalMix but only on pc reboot.

Windows halts after beginning the restart process. Error dialog box reads:

TMFXCallback: TotalMixFX.exe - Application Error

X  The instruction at 0x0000000000000000 referenced memory at 0x0000000000000000. The memory could not be written.

Click on OK to terminate the program.

Under the error dialogue I get buttons that say "Restart anyway" and "cancel" as the options.

If I Cancel, Windows stops the restart process, I can kill TotalMix manually, and try rebooting again, or I can select 'Restart anyway.'

I see there's maybe a new version of TotalMix and/or driver updates coming out? Any clue as to whether they'd be pertinent to this?

Thanks again RMErs. : )