Problem between Wave software and power management on a Latitude D420

Hello, first post here, I believe I haven't seen anybody writing about this problem yet.

 

On a client's Latitude D420, we have the following strange behaviour of the fingerprint reader: if the computer is woken up from standby mode after less than ca. 2 hours, the Wave logon window (fingerprint+password) works fine (the system is configured to ask for authentication when resuming from standby). If the standby period was longer than 2 hours, the Wave logon window never shows up and we must reboot the computer to be able to login again, loosing all unsaved data. I am not sure whether this is a fingerprint reader or Wave Embassy or Windows power management problem.

 

Now about what we did already:

- patched the Embassy software to the latest version;

- checked that the BIOS-level biometric authentication is off;

- disabled "turn off this device to save energy" in Device Manager for the fingerprint reader;

- obviously, disabling authentication on resuming after standby solves our problem, but our client precisely wants to authenticate in this scenario;

- called Dell support a few times without success;

- wrote to the Dell client advocates on 11/29 to complain (we've been asking for help for more than 3 months now) without any answer yet.

 

Anybody could help? I would be especially grateful if someone would check out whether their computers also fail to show the Wave logon window after 2+ hours of standby.

 

Thanks in advance!

 

Robert