Windows Booting very slow after 2004 update ,

Hello @Jaavenor - this is a known Microsoft bug/issue, and some call it password "amnesia". It is a subtle bug in a scheduled task on some configurations, that ends up erasing a password decrypt key in LSASS:

Until Microsoft delivers a fix, its recommended workaround involves right-clicking the Windows 10 Start Button and selecting Windows PowerShell (Admin). If not there, right-click on the Start Button, select Command Prompt (Admin) then key in powershell. It depends on how your "start" is set up.

Microsoft then recommends:

1. Copy and paste the command below into Windows PowerShell and press Enter.
2. Get-ScheduledTask | foreach { If ((xml).GetElementsByTagName("LogonType").'#text' -eq "S4U") { $_.TaskName } }
3. If you see any Tasks listed from the PowerShell output, make a note of them.

Next, go to Windows Task Scheduler and disable any tasks you found from the above command.  Follow these steps:

1. In the Windows 10 Search box, type Task Scheduler and then open the Task Scheduler app.
2. Locate the task in the Window (e.g.HP Customer participation), or other task from the Windows PowerShell output.
3. Right-click the task and choose Disable.
4. After you disable the task, restart Windows.

Microsoft notes that users may need to re-enter missing passwords one more time before it is saved again.

I did the same to my Asus laptop - reinstalled 2004 that later updated to 20H2.  I also installed a SSD.  All went well until Microsoft 365 Outlook, each time launching, decided to ask me for a password for each of my four email addresses, Onedrive and pin number.  This would continuously happen - even sometimes wile I was using Outlook.  Not even Geek Squad has figured it out.  I delivered the laptop to them for the third time - have not heard from them in a week.

I have a Surface Pro 6. It used to boot in approx. 10 seconds, after 2004 update it has become 90 seconds boot time. I was so annoyed.

That's why I am here in this thread.

After trying everything that listed here, I ran DISM, SFC, turn all the excessive processes off, etc. Nothing helps.

So I decided to click the reset button and gonna bite through installing all the apps again.

It works!

Now my Surface in back to 10 secs boot time.

And I'm on the way to re-install most of my applications.

Thanks for your info - my PC will not install 2004 with failure code Oxc 1900101.  Have tried the troubleshoot, updater drivers, etc., but with no success.  So far the computer has initiated eleven tries of download and install 2004- all have failed.

On my laptop that was dramatically slowed by the install of 2004 - I had a SSD installed - major speed improvement and now running 20H2.  Problem now is each time I boot email client Outlook, I'm asked for the passwords for the four emails I use including my Microsoft password.  Sometime when I boot the computer it asks for my Onedrive password.  Sometimes when I'm typing an email the password requests pop up. The laptop is now at Geek Squad for the third time - they have not figured it out why the annoying repeated request either.  I'm beginning to think build 20H2 may have something to do with the problem.

Not sure if its been posted here as i only read the first few pages of the thread, i had started getting very slow boots, checked the logs and the pause seems to happen with winlogon, after searching threads i stumbled on one that showed that having network locations mapped was the problem, i literally just deleted the network locations (i.e. mapped drives on another pc) from "This computer" and boot was back to normal