This one is a little of a workaround: Windows Vista and Windows 7 Black Screen on Computer Unlock: Symptoms:
Consider the following scenario:
1. A Windows Vista or Windows 7 computer is running the “Aero” graphics mode.
2. The Windows Vista or Windows 7 computer is subject to additional security restrictions and security software, such as might be the case in the enterprise, or with mandated security settings and software such as DISA or DoD requirements.
3. The computer is locked and left undisturbed long enough for the screen to go black, which is 20 minutes with the default power policy of “Balanced”.
4. A person unlocks the computer by entering their user credentials.
After the credential are entered the screen goes black, and remains black for as much as 10 minutes or longer. The machine is not “hard-locked”, as periodic disk-drive activity may be noted from the disk-drive indicator light on the computer, if so equipped. Cause:
A problem with some layer of security software causes the Desktop Window Manager
to wait for an unspecified amount of time. Resolution:
1. A temporary workaround is to Stop
the “Desktop Window Manager Session Manager
” service. Disabling this service will turn off the “Aero” graphics display feature, which will disable certain features such as Aero Peek, Aero Snap, Aero Shake
, and so on. To disable this service:
a. Click the Start button, type “services.msc” and then press the ENTER key, or click the icon that comes up under “Programs” in the Instant Search box.
b. Locate and then double-click the Desktop Window Manager Session Manager
c. Locate the “Startup type” dropdown and change the value to “disabled
d. Locate and click the button labeled “Stop
e. Click the Apply
button, and then click the OK
Alternatively you can run the following commands from an elevated CMD prompt to set the service properties of the Desktop Window Manager Session Manager
service to not running and disabled:
net stop UxSms
sc config UxSms start= disabled
To return the settings for the Desktop Window Manager Session Manager service to normal via the CMD line:
sc config UxSms start= auto
net start UxSms More to read: Windows Vista and Windows 7 Black Screen on Computer Unlock