Latitude E6540 very slow on bootup after Windows 10 Anniversary Update Build 1607

Hi,

I am wondering if anyone else is experiencing this problem after the Windows 10 Anniversary Update.

When restarting, my laptop takes 5 minutes (no, that's not a misprint) to bootup. More specifically, that's the time taken from pressing the On button to the time I get to the login screen. I have an SSD drive in the laptop. While I am waiting for this to happen, the drive light is permanently on with no flickering. That's a LOT of drive access / throughput.

From there (logging on), there are no issues. Laptop is fine.

Here's a very weird thing. If I run cmd as Administrator and then run chkdsk /f and then reboot, the laptop (after it does the disk check and reboots again) will start really fast. Like it should. If I then reboot after that, it's back to the five minute thing.

I have tried the following:

• Turned EnableULPS off
• Tried turning off Virtual Memory or adjusting it to the recommended settings
• Turning off Fast Boot
• Taken the battery out while machine is off
• Updated the drivers from the Device Manager
• Unfortunately boot logging c:\Windows\ntbtlog.txt does not show log times and so I cannot see where the delay is.
• Nothing in the Event Viewer since the delay happens before that.

Any ideas? The E6540 is supposedly certified for Update 1607. 

Many thanks.

Kind Regards

Nick