Differential encoder hard crashes the PC MESA7i77

Also, as of now everything is new on the PC. I have an older dell optiplex I can play with if we think thats the issue…

I don't see anything obvious wrong in the hal/ini files

I would try using and external 5V supply  as a way to debug the issue
but its a pretty mysterious problem.

I had a few more minutes to work on it this week - I wired the encoder via a short pigtail to the 7i77, got the same results as before. So the issue cannot be a faulty wiring connection.
I also found that my 5vdc power supply may not have been grounded, so I fixed that, no change, the PC still crashes.
I also tried all the other encoder locations on the 7i77, all producing the same issue.

I will keep updating as I do more.

Do you have any normal encoder, or a servo motor with encoder attached to it?
If yes, wire it and test, see if the same thing happens.
Do you have the spec for the MPG?

Another thing to try:
-set the Mesa encoder inputs to "single ended" for that channel (see manual)
-Wire only +5V and GND-
-wire only A+ and B+ from MPG to Mesa A+ and B+
-test
-wire only A- and B- to Mesa A- and B-
-test
?

If you are not overloading the 5V supply on the 6I25
I really don't see how any wiring or data issues can
crash the host PC.

That is, this really has nothing to do with differential
encoders at all.

I'm beginning to wonder if this is not a parity error or similar
either in the host PC or PCIE interface

Did you say the you only got the error when you changed the MPG position?