Code 52 - CM_PROB_UNSIGNED_DRIVER
This Device Manager error message indicates that the device did not start on a 64-bit version of Windows because it has a driver that is not digitally signed. For more information about how to sign drivers, see Driver Signing.
"Windows cannot verify the digital signature for the drivers required for this device. A recent hardware or software change might have installed a file that is signed incorrectly or damaged, or that might be malicious software from an unknown source. (Code 52)"
The driver does not comply with the kernel-mode code signing policy.
For end-users, the only way to avoid this error is to obtain and install a digitally signed driver for the device.
For driver developers, you can use various methods to load an unsigned driver on a 64-bit version of Windows. For more information, see Installing an Unsigned Driver during Development and Test.