[loribinca]

Just picked up a type cover for my surface RT (I was originally using a red touch cover) and device manager has a warning against the Surface Type Cover Firmware Device

it says that it cannot verify the digital signature for this file.

did the 8.1 upgrade mess this up?

Anyone Else got this?

[Need4Geek]

The 8.1 Preview update is probably the cause of this issue. Try to get back to Windows 8 and plug the touch cover again.

[webwevers]

After the 8.1 update mine gives me the same warning, I also get the warning with the touch cover. I have noticed some problems with both touch and type covers when typing in the search box and when trying to log in to my email, hopefully they will correct it ASAP

[Laibalion]

Try to uninstall the "Surface Touch Cover Firmware" driver. Make sure to also check "Delete the driver software for this device" as well.
Once done, just press the "Scan for hardware changes" button and it will re-add the driver automatically.
The error should be gone now.