I am running Windows 8.1 64 bit, and have QGIS 2.4 and 2.6 installed. When I try to use a GRASS 6.4.4 vector command (specifically v.clean), I receive an error message in an endless loop, and the only way to cancel it is to close QGIS. This happens for both 2.4 and 2.6, and I have tried uninstalling and re-installing GRASS.
This is the error message I recieve:
and this is how I have GRASS set up: