Sleep and Hibernate troubleshooting

For the Standby, Sleep, or Hibernate modes to work properly in Windows 7, your PC has to cooperate. If it doesn't, you might experience a problem such as:

No sleep
Windows won't go to sleep at all; either nothing happens when you try to stand by, or the system just crashes in the middle of the process.

No wake up
Windows won't wake up after going to sleep, or Windows simply boots normally instead of resuming your previous session.

No more sleep
Windows goes to sleep or hibernates once, but once it wakes up, it won't go back to sleep until you restart it.

Features are unavailable
Some or all of the power management features and settings discussed earlier are grayed-out (disabled) or missing.

Stuff stops working
Some features, like your wireless network, your cordless mouse, or your scanner stop working after waking up, at least until you restart Windows. (Hint: look for new drivers or a firmware update for your device.)

Unfortunately, all of these problems are quite common, mostly because of the inconsistent support for Advanced Configuration and Power Interface (ACPI) in the computer industry. The good news is that there are a few things you can do to help improve your computer's support for APM and ACPI, should you be experiencing any of these problems:

Update your PC's BIOS
Check with the manufacturer of your computer system or motherboard for a BIOS update. 7 requires that your BIOS comply with the ACPI 2.0 specification.

Enable ACPI/APIC
Enter your BIOS setup screen, and make sure the ACPI APIC support setting is set to On or Enabled. If you see a setting referring to ACPI 2.0 or some later version, try turning it on if it's off, or vice versa. Reboot your PC when you're done. Depending on how ACPI-compliant your PC is, it may take some trial and error to get 7 to sleep properly.

Fix or disable Hybrid sleep
The second most common cause of sleep and hibernation problems, behind an out-of-date BIOS, is a video card (display adapter) driver that doesn't support Window' Hybrid Sleep feature. Check with the manufacturer of your video card for a newer driver, or try turning off Hybrid Sleep.

Disable power saving for your wireless adapter
As with the video card, make sure you have the latest driver and firmware for your wireless adapter. Also, try changing the device's power settings: in Device Manager, double-click your wireless network adapter. Choose the Power Management tab, and turn off the Allow the computer to turn off this device to save power option.

Free up some disk space
As explained earlier, the Hibernate feature creates an image file on your hard disk equal in size to the amount of installed memory. If you have 2 GB of RAM, then Windows will need 2,147,483,648 bytes of free disk space for the hiberfil.sys file. If hibernation doesn't work, or if it's exceedingly slow to initiate or recover, try deleting the hibernation file as described previous in "What Is hiberfil.sys?". Then, defragment your hard disk, and re-enable hibernation.

Perform a Sleep test
Go to http://www.passmark.com/products/sleeper.htm and download the free PassMark Sleeper tool to help test your computer's ability to enter and recover from Sleep, Standby, and Hibernate modes.

Keep in mind that you may never get your system to reliably go to sleep and wake up; but if you are able to get this feature working, it can be very convenient.