Error Message Explained: User Profile Service Failed the Logon

Error Message Explained: User Profile Service Failed the Logon
This article is part of Helge’s Profile Toolkit, a set of posts explaining the knowledge and tools required to tame Windows user profiles. Many errors related to user profiles result in the user getting a temporary profile instead of the regular local or roaming profile. I have written about possible causes for that here. In addition to that, there is an entirely different category of errors that occur when even a temporary profile cannot be created. This article describes likely causes.
User Profiles

Boot IO Analysis with uberAgent for Splunk 1.5

Boot IO Analysis with uberAgent for Splunk 1.5
Analyzing slow boots is a difficult task. You need to install software like XPerf and master its far-from-intuitive command-line options to generate a trace file that you can then analyze. Once you find a possible cause for the long startup duration you never know if it is specific to the machine you analyzed or if it affects other PCs, too. In other words: XPerf, although powerful, is difficult to master. And it does not scale. uberAgent does. And it is super-easy to use.
Logs & Metrics

Contest: Why Is This Desktop Empty?

Contest: Why Is This Desktop Empty?
I just had a situation where I was facing an empty desktop with no way to logoff, start a program or do anything else. The only thing left to do was to log the session off from an admin session. This got me thinking: how many ways are there to create such a situation? I am writing down all the ways I know of and ask everybody to contribute. Can you come up with a way to end up with a completely empty desktop I and no one else thought of before?
Citrix/Terminal Services/Remote Desktop Services

How-to: XenApp/RDS Sizing and Capacity Planning with uberAgent for Splunk

How-to: XenApp/RDS Sizing and Capacity Planning with uberAgent for Splunk
Do you know the maximum number of users each of your terminal servers can host with acceptable performance? You may have found out the hard way how many are too many - but how many are just right? Farm sizing and server capacity planning are typical tasks for consultants who often have a hard time fighting the peculiarities of perfmon and logman trying to get the data they need for their calculations. It can be so much easier at no additional cost. The 60-day Enterprise Trial version of Splunk in conjunction with an evaluation license of uberAgent give all the information you need in much less time. Here is how.
Citrix/Terminal Services/Remote Desktop Services

Monitoring Browser Performance per Site with uberAgent for Splunk

Monitoring Browser Performance per Site with uberAgent for Splunk
The days are long gone when a browser was just another application. Modern websites are applications of their own, and the browser is their operating system. That has consequences for monitoring. It is no longer sufficient to gather performance data for the browser as a whole. When, for example, Internet Explorer’s CPU usage is high, Administrators need to understand what caused that. Is it the business-critical ERP site or are people just watching fun videos on YouTube?
Logs & Metrics

The Impossibility of Measuring IOPS (Correctly)

The Impossibility of Measuring IOPS (Correctly)
If you have ever used Sysinternals’ Process Monitor, chances are high you were a little intimidated when you looked at your first capture: it probably contained hundreds of thousands of registry and file system events, generated in a minute or less. That amount of activity must surely indicate high system load - but strangely, very often it does not. Looking at the hard disk LED you will only see an occasional flickering, even though thousands of file system events are captured per second. How is that possible? Read on to find out.
Performance/Sizing