MS Hyper-V Network Switch shows error 39

I recently noticed that Event Viewer shows a warning that "The driver \Driver\VSMMP failed to load for the device ROOT\VSM_MP\0000. Device Manager shows a yellow triangle for MS Hyper-V Network Switch Default Miniport. Clicking on it shows error 39.

I have tried to uninstall it in order to reinstall it, but it won't uninstall. I have no idea what this switch does or how the failure to load this driver may or may not affect my network. I am running Windows 8.1 Pro (64 bit). Searches show others have reported similar problems, but I have not found a fiix. Any help would be appreciated.