My Windows 7 Ultimate woke up mysteriously with the following event logged: The system has resumed from sleep. Sleep Time: ‎2010‎-‎04‎-‎08T02:49:42.906027300Z Wake Time: ‎2010‎-‎04‎-‎08T04:15:26.007905000Z Wake Source: Unknown This happened before. I am wondering if anyone could offer a tip on how to find the cause. Thanks in advance.hz

Hi hipswich, You can refer to the suggestions in this thread to see if it can be resolved: Computer refusing to go into Sleep Mode Also, here is Sleep and hibernation: frequently asked questions. Regards, Linda

Thanks, Linda, for the tip. I followed the instructions and could not find any suspects because the only three devices that are allowed to wake up the computer - mouse, keyboard, network card were not touched. The noticed that the first logged system event after the mysterious wake-up is the following: The system time has changed to ‎2010‎-‎04‎-‎08T04:15:12.500000000Z from ‎2010‎-‎04‎-‎08T02:50:01.714014300Z. I am wondering if this has anything to do with the wake-up. hz

Did you try Powercfg -devicedisablewake "devicename" command to disable the network adapter from waking the computer? If not, it is recommended you complete the steps to check the result: 1. Click the Start Button, type "cmd" (without quotation marks), right click on the "Cmd.exe" in the search result list and select "Run as administrator". 2. Type "powercfg -devicequery wake_armed" (without quotation marks) in the open window and press Enter Key. 3. A list of the configured devices to wake the computer will be received, then please type the following command to disable them one by one and see if the culprit can be found. (We may test the result after disabling each device.) Powercfg -devicedisablewake "devicename" Note: "devicename" is a device name listed as a result of running the first command. For example, if the network card "Broadcom NetXtreme Gigabit Ethernet" is listed, we can type the following command to disable it and press Enter. Powercfg -devicedisablewake "Broadcom NetXtreme Gigabit Ethernet" 4. Please repeat the steps for other devices in the list. 5. Reboot the computer and check this issue again. What is the result now? Regards, Linda

I went to the Power Management Tab of all the devices that were allowed to wake the computer (totally 3) to disable it. Now it shows nothing if command "powercfg -devicequery wake_armed"is run. The unexpected wake-up has not happened so far. I will report back if it happens again. Thanks again for all your help.hz