Windows 10

[8-Bits]

First, to answer my own original question I created a Win10 bootable DVD and did a repair of the OS and my Printrbot SM is now working fine. In fact, it's directly supported by Win10 and shows in the device list and Explorer window as a named 3D printer. My guess is now that Windows has a built-in USB-to-Serial driver there was a conflict with the old "unsigned" driver that was needed with Win7. I also have a FlashForge CP running with Win10 (using RelicatorG, Repetier, MakerWare and Slic3r) and everything appears fine. I would suggest that if you decide to update to Win10 you first uninstall the affected driver.

To clarify the "automatic update" function of Win10, the Pro (and Enterprise) version does indeed let the user stop automatic updates. It is only the Home version that removes that option. And all versions let you hide and uninstalled an update just like all previous versions of Windows. This actually makes sense for the millions of average users that tend to let there OS security updates fall behind. This is the same approach used by most anti-virus apps.

Ref: http://windows.microsoft.com/en-us/windows-10/defer-upgrades-in-windows-10