Windows 8 Slow boot time, high disk profile and hangs at startup

I spent long time helping in deploying Windows 8 in big enterprises by testing the new O.S when it first shipped, and validating application compatibility. I have played with the original Windows 8 and Windows 8.1 ISO files in many ways. I used WDS to deliver the image [Check this post], and i even created a custom image pre-loaded with corporate software [Check this post].

I thought everything is cool, until we started to hear some feedback about slowness. Across 2000 Windows 8/8.1 sample machines, the feedback about slowness was so strong that we could not ignore anymore. We identified the problem as per the following:

When booting a Windows 8 or Windows 8.1 machine, and after entering the credentials to log on, the desktop freezes for about 3 minutes before everything suddenly start to respond. High disk profile is noticed from while to while also. This only happens after joining the machine to the domain

Investigation

We started to suspect that our custom Windows image is causing the slowness, so we started to redeploy Windows using the original ISO without any modification. This did not help.

We started to suspect the big number of group policies that the corporate has. The AD team started to consolidate group policies so that instead of applying corporate settings in the form of 25 group policies, now they reduced it to 8 policies. This did not help also.

Logs are clean, nothing is crashing. We suspected that the AntiViurs is causing such slowness, or even the data loss prevention solution deployed to workstations. Another  dead end. Problem did not go away.

One interested fact is that this slowness happens after joining the machine to the domain. We did the following to understand why joining the machine to the domain causes this slowness:

– Create an OU in AD  called “Investigating Slowness”

– Apply Block Inheritance on that OU, to prevent any group policies to be applied on machines under that OU.

-We created a computer account called (Machine1) under that OU, then we formatted a new machine with the same name, and we joined it to the domain.

– We confirmed that slowness is not happening so far even after joining the machine to the domain. So we suspected a group policy setting.

– We started to link one group policy at a time to the “Investigating Slowness” OU, and reboot the machine each time and monitor if slowness is happening.

– Finally we found the cause of the problem !

Solution

The reason behind the slowness is simply the BranchCache policy that is applied via group policy. The policy configures the BranchCache to be set to Automatic and it configures Distributed Cache mode.

I read about enhancement in BranchCache for Windows 8 and Windows 8.1, and it was a big shock for me to know that the reason of such slowness was caused by BranchCache in Distributed mode.

Anyway, after removing that group policy, machines are operating faster, and they are not freezing after booting and signing in.

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