IP-Symcon crashing nearly every night


after years of more-or-less stable performance my IP-Symcon server started failing at night.
Last 2 weeks ca. 5-6 times.

The error I found in log files:

Warning:  I/O Instanz ist nicht aktiv in...

In console, FTDI indicates an error, Device is empty and error text says that ‚EL5M377Y‘ is not available.

In a Windows device manager, there’s the following error:
"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. "

System runs on WHS 2011 server.

I do not understand why the driver gets corrupted „at runtime“, after it was successfully installed and used.
It starts to work again after reboot.
I did not find any solution using google.
Any advice?


The device might be broken and kill the service…