Event 2019 “The server was unable to allocate from the system nonpaged pool because the pool was empty”

Symptoms:

System and applications slow-down and then hang indefinitely
Authentication errors
Unable to logon or logoff
Eventual loss of network connectivity
Many errors in the event log, seemingly random and mis-leading
Pop-up errors complaining of “insufficient space” or “insufficient resources”…
A reboot fixes it temporarily, but then the issue happens again after a few hours, or sometimes days.
**If you happen to have task manager running during the issue, CPU and Memory look normal, and the system drive has plenty of free space.


Resolution:

Even though symptoms appear to point to other things such as authentication errors, registry I/O errors, or even disk performance counter errors, the root cause is something completely different. In all of the cases I’ve looked at, the issue turned out to be a faulty driver that was slowly consuming all of the nonpaged pool in kernel memory. This article explains how to find which driver/process is consuming the kernel memory:

http://blogs.msdn.com/ntdebugging/archive/2006/12/18/Understanding-Pool-Consumption-and-Event-ID_3A00_--2020-or-2019.aspx#ntdebugsurvey2

Important tools to have installed when troubleshooting this issue:
- Poolmon.exe (included with the Support Tools, the article explains where to get this)
- Process Explorer from Sysinternals
- Windows Debugging Tools