A few days ago I was troubleshooting some strange problems on a Citrix Server. After some investigation (I will write about that later) it was clear to me that there was a shortage of System Page Table Entries (PTE’s). Using perfmon you can see how many free System PTE’s are available:

Any value below 5000 is not good, values below 2000 are critical. In my case it wasn’t possible to view processes with Task Manager anymore.

Next I used WinDbg and attached to the Kernel (you can do that with File | Kernel Debug | Local | OK) and issued the !vm command:

WinDbg shows us a warning that a lot of PTE allocations have failed, we can also see that there’s enough Paged Pool and Non Paged Pool available.

So how do we find the guilty driver (usually it’s a driver)? (more…)

I have found and tested some new functionalities which I will add to SasLibEx:

• Unlocking workstation without entering password
• Cancel UAC (User Account Control) request
• fully disable Ctrl-Alt-Del
• Cancel Ctrl-Alt-Del
• Switch between secure desktop (where the UAC prompt is) and the normal desktop.

Some people asked if SasLibEx works on x64 or Windows 7, the answer is yes. I tested on build 7000 of Windows 7 beta and also on Server 2008 x64.