Windows: Login to client in a domain extremely slow because of TEMP files

[German]Some days ago an administrator reported in my German blog that he had this problem when logging in to Windows clients that were members of a domain. After various tests, it turned out that very many files in the TEMP folder of the user profile are the cause of this behavior.

Slow login due to many TEMP files

German blog reader Peter found my German blog post Windows-Start per Process Monitor analysieren (Analyzing Windows Startup via Process Monitor), where I've described how to use the Windows Process Monitor from Sysinternals tools to analyze Windows startup. He had a problem in his environment that Windows clients took a very long time to log on to a domain. In this comment he wrote (I translated it):

I stumbled across the article after having problems registering a machine in the domain. Unfortunately, the Process Monitor output is extremely cluttered, as there were what felt like a million entries.

Our problem ultimately had a very mundane cause: the user's temp directory (C:\User\Name\AppData\local\Temp) had over 300,000 files and umpteen subdirectories. After emptying the directory, the login was much faster.

It went from what felt like 60 seconds to under 5 seconds for the time from logging into the domain to starting the desktop.

The complete cleaning of the directory was done in this case via another profile. Otherwise it also works via your own profile, but there will be files you can't delete because they are open.

Thanks to Peter, who left a feedback and wrote: "This may help one or the other, especially since it is quite easy to implement."

Slow startup and logon analysis

If Windows takes a long time to start, shut down or log on, this can have very different reasons. Sometimes a search on the Internet is enough to find out possible causes. If the problem occurs after an update, it can be tested very quickly by uninstalling this update.

However, in all cases where the cause is not immediately clear, the only thing left to do is to analyze the process in question. I had presented different approaches in various articles here in the blog. For example, the Windows Performance Recorder and the Windows Performance Analyzer of the Windows Assessment and Deployment Kit (Windows ADK) can be used to analyze the startup, logon and shutdown processes. I had outlined the procedure a few years ago in the German blog post Windows: Start, Herunterfahren, Ruhezustand analysieren. Personally, I haven't used the tools in a long time, and the techniques should still work on Windows 10 and Windows 11.

Another option is to track and analyze Windows startup with Windows Process Monitor from Sysinternals Tools. The free tool allows logging of the boot processes. I had described the basic approach in the German blog post Windows-Start per Process Monitor analysieren. However, the evaluation of this logging is not always easy because of the many entries.