Driver signature error on Windows 7 (error 52)

The Spectrum hardware driver is not working and shows error 52 (Windows cannot verify the digital signature for the drivers required for this device). Either your system is set-up new or you encounter this error message after doing a Windows update.

What's happening here since Spectrum driver V3.21 (20/May/2016):

The Spectrum drivers now use the SHA-2 code signing algorithm. On a fresh installed Windows 7 system (without updates) is this signing algorithm unknown. At Windows 8 and newer is this algorithm by default available.

How to get around it

This should normally get installed with the automatic operating system updates (if enabled) or can be manually installed in two ways: either as a single small update with KB3033929 or as a huge update together with the latest Convenience Rollup KB3125574

You can check if one of this updates is installed, with following commands:
wmic qfe | find 3033929
wmic qfe | find 3125574

After installing one of this updates, the error 52 should disappear. The following part is not necessary for the above error reason.

What's happening here since December 2014:

In December 2014 Microsoft released a Windows 7 update (KB3004394) that is automatically installed if you have Windows updates activated. This update re-news the Windows root certificate but could cause some problem with signed drivers and software. If you do a google search on the keywords KB3004394 and problems you will read quite a lot of the side effect this update generates.

On some systems this update could prevent the Spectrum drivers for all M2i/M3i and M4i cards to load properly.

How to get around it

Meanwhile the update is no longer available from Microsoft but where it has been installed it unfortunately need to be uninstalled manually:

• Go to the control panel (Start button)
• Programs
• Programs and Features -> View installed updates
• Search for the update KB3004394 and uninstall it
• reboot