I have a problem where one system periodically will not enter standby (S3 or hibernate). Logging off any users and logging back in does not resolve it, only a reboot. The right power plan is definitely selected. Powercfg tells me that standby is being prevented (SYSTEM request) by the DRIVER "Legacy Kernel Caller". Unfortunately, even specifying -requestsoverride for this driver does not work. Powercfg seems to tell me it is correctly configured but still no sleep! There is remarkably little info in the whole of the web on this "driver". There appear to be a few people with specific apps (none that are installed on this system) that have seen the same issue, but no general solution. Anyone know what kind of thing causes this and if there is any way to get -requestsoverride for this driver to actually work? Thanks.

Update all drivers. 1 driver seems to block entering Sleep. Can you please run msinfo32.exe and upload the summary here?"A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/

Hi, By any chance, did you update your audio driver recently? I'm having the same problem as you, and the only recent system modification was to update my Realtek Audio drivers I think.

What is the model of your computer? You may get drivers from the computer manufacturer's website.Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Do you have any known programs, processes or drivers working in compatibility mode? Or may be being forced to work in compatibility mode without your knowledge? Does it do that when you load up a basic startup? (clean boot they like to call it)