2008 R2 Terminal Server: “Insufficient system resources exist to complete the requested service”

rdsresource-managementterminal-serverwindows-server-2008-r2

I'm working with an unhealthy Windows 2008 R2 Terminal Server configured in a vSphere environment. It currently has 4 vCPUs and 32GB RAM. No overcommitment.

The concurrent user count on this server has risen sharply in recent months (~70), and is possibly over the recommended level. Due to the applications used by the users on this system, splitting this into multiple servers will be a challenge beyond the scope of this question.

However, at certain points during the week (and now, almost daily), new user logons produce the following errors: Event ID 1500

Windows cannot log you on because your profile cannot be loaded. Check
that you are connected to the network, and that your network is
functioning correctly.

DETAIL – Insufficient system resources exist to complete the
requested service.

This remains until some users log off, sessions are manually disconnected or the system is rebooted entirely.

I'd like to know:

  • What resource(s) is this error message referring to? What's actually constrained?
  • Is there an OS-level tunable or configuration that can help with this?
  • Users are content with performance, except for the increased frequency of this error message. Is there something else at play here?
  • Is there an absolute limit to the number of users a terminal server can accommodate? I see 150+ users described in certain tuning guides for Terminal Servers.

enter image description here

enter image description here

Best Answer

This has been solved.

I began to examine the registry because increasing CPU and RAM resources on the virtual machine did not resolve the issue.

I was pointed to Microsoft's dureg tool to estimate the registry's size. Browsing via regedit, I encountered issues opening the keys under HKEY_USERS\.Default\PRINTERS. Using dureg, I started probing under that hierarchy.

Printers were the problem. The cause and fix are detailed in:
The size of the "HKEY_USERS.DEFAULT" registry hive continuously increases on a Windows Server 2008 R2 SP1-based server

Hotfix: http://support.microsoft.com/kb/2871131

This apparently stops the growth, but the keys and registry need to be compressed to reclaim space.

Compressing bloated registry: http://support.microsoft.com/kb/2498915

1)  Boot from a WinPE disk.
2)  Open regedit while booted in WinPe, load the bloated hive under HLKM. (e.g. HKLM\Bloated)
3)  Once the bloated hive has been loaded, export the loaded hive as a "Registry Hive" file with a unique name.
4) Unload the bloated hive from regedit.
5) Rename the hives so that you will boot with the compressed hive.
e.g.
c:\windows\system32\config\ren software software.old
c:\windows\system32\config\ren compressedhive software

Hmm, a few steps... kinda tricky to do remotely during production hours. I tried to reach out to my resident Microsoft expert to complete, but he was busy chasing down some SCCM or SCVMM issue somewhere. Reading through some Citrix-related forums, I took note of a tool that could perform the above with fewer steps...

So I took a virtual machine snapshot, then downloaded and ran freeware registry compression software (Tweaking.com); despite the overwhelming sound of the collective groans of Microsoft systems engineers everywhere...

note the 1.4GB saved in the default Config... tucows

PLEASE REBOOT!

Following a reboot, all was well. The user count reached 86 with no ill effects and no profile-related errors. I've monitored the printer registry hive and it's held stable.

Related Topic