I went a bit further than that.

I backed up my stuff onto another hard drive, then did a complete format. I loaded up an SE Navcore, and used the switchfile setting to delete the flash. I then reformatted and put 9.051 ME on my unit.

I'm counting the days when I get my next mark map location issue, if deleting the flash is a workaround.

OK, can we consider this problem solved?

Yup, I'll let you guys know if the problem comes back describing exactly what the situation is that causes the problem to reappear, if that does happen.