hi, started up my machine the other day,(ver 066) and I found that when  programed with a G00 in a program or with midi, it didnt pick up either the velocity or acceleration settings and would attempt to go flat out from nothing,faulting the servos.However if you jogged it at rapid with the keyboard it did pick these settings up.
Caused quite a bit of head scratching untill I worked out what was going on. shutting the program down and re starting it cured the problem I didnt need to re-boot the computer. I have noticed freaky servo faults in the past which are begining to make sence now.

   Also If I re-install mach will it overwrite all my settings and toolchanger files?

Regards
   Tony

Never heard of that problem before but in my opinion (and experience) 066 and 067 have lots of issues and I do not use them.
Hood

use 3.043.022

3.043.022 has a serious bug with non standard tool change macros.