Windows Booting very slow after 2004 update ,

I did notice something similar. In mid-July when I went from v1909 to v2004 the boot time became a diabolical 10 minutes but over a period (not sure how long) it dropped to an atrocious 6 minutes where it stayed. Only in mid-September did I try to make it better, like disabling SysMain (since re-enabled), stopping only at the more extreme solutions like installing an SSD, re-installing Windows 10, or going back to v1909, which each seemed too much effort for a potential saving of 5 minutes per boot.

@DanDScan I have copied your useful post informaton about the registry change, to the Microsoft "AskPerf" blog post, set up by the performance group manager. Hopefully they might review your findings, but I am not sure what "exposure" it actually gets.  I hope you don't mind me doing that, but I suspect that the "Performance group" is driven from above, rather than user input, but is worth a try.

It is here if you want to take a peek:

https://techcommunity.microsoft.com/t5/ask-the-performance-team/welcome-back-askperf/bc-p/1920044

It might also be worthwhile you putting your useful info into the Feedback Hub, in the hope that the more it is mentioned, and "upvoted", the more MS might take an interest.

I tried disabling SysMain (aka SuperFetch/Prefetch) but this did not help. I re-enabled it and over the next few days the boot time gradually came down to what it was before updating to version 2004.  I am guessing but what may have happened in that initially everything was loaded on start-up, but then gradually SysMain or something else only initially loaded those Windows programs which I use. 

Incidentally the version 2004 major update was followed a few days later by the 20H2 minor update. I understand that subsequent updates will use the yyH1or 2 format.

I have tried most of the solutions proposed for the long boot time with version 2004 and none has worked. I have now found a solution that does work on my computer. From login to useable screen was taking about 6 minutes and now takes 75 seconds which is the same as with previous versions of Windows 10.

Machine: Laptop, Intel i5, single HDD, Windows 10 Pro 2004

In the registry I have disabled Autorun for the HDD – see Microsoft’s documentation in the reference at the end of this post. One difference is that I have this key under HKEY_LOCAL_MACHINE rather than Microsoft’s recommendation of HKEY_CURRENT_USER.

Using Regedit create the following key (if it’s not already there):

HKEY_LOCAL_MACHINE

    Software

      Microsoft

         Windows

            CurrentVersion

               Policies

                 Explorer

Then create NoDriveTypeAutoRun as REG_DWORD with value 0x08 (decimal 8)

The possible values are:

Bit Number       Bitmask Constant                     Description

0x04             DRIVE_REMOVEABLE         Disk can be removed (such as a floppy disk).

0x08             DRIVE_FIXED                       Disk cannot be removed from drive (a hard disk).

0x10             DRIVE_REMOTE                  Network drive.

0x20             DRIVE_CDROM                    CD-ROM drive.

0x40             DRIVE_RAMDISK                 RAM disk.

All other solutions proposed under earlier posts have worked for some users but not all and I suspect this solution will be no different. Still, this solution has zero cost, is easy to apply (if you are used to using Regedit) and is reversible. Hopefully, a few more users will find themselves dug out of the slow-boot hole.

Note:

I have not tested with Microsoft’s recommendation of using HKEY_CURRENT_USER.

Reference:

https://docs.microsoft.com/en-us/windows/win32/shell/autoplay-reg

Acknowledgement:

Kaspersky’s Total Security ‘Vulnerability Scan’ tool

I too have tried all the suggestions here and got the boot time down from several minutes. Tried your suggestion via the Kaspersky app and sure enough it found the autorun and disabled it by adding the entry in the registry. It set it to 3c and I changed it to 7c so all are disabled. Boot time is quicker after password entered. It takes about 10-15 spins of the busy cursor to usable Windows...

Thanks for this info. Strange but works.

I agree that it is a dramatic and surprising result and not at all what I was expecting. I can’t explain why it works as I have no tools to interrogate the early part of the boot process to see what actually is going on. Within Kaspersky Total Security is an analysis tool called ‘Vulnerability Scan’ which I ran with no thought of the slow boot-time. It came back with ‘Autorun from hard drives is enabled’, ‘Autorun from network drives is enabled’, ‘Autorun from removeable drives is enabled’ with suggestions to correct by disabling these entries.

Kaspersky further says that “If the autorun from hard drives option is disabled, then it will not impact your system boot and your system performance. The fix disables only the autorun of the autorun.inffile, which can contain links to launch malicious programs. By default the autorun from hard drives option is disabled.”

Subsequently, when I saw the boot process had speeded up, I did some digging to determine what had changed and a search of the registry found the NoDriveTypeAutoRun entry with a value of 0x1c (decimal 28) covering the three drive types. A test showed the HDD entry alone was sufficient to speed-up booting, value 0x08 (decimal 8) as in my post.

A common feature of the very slow boot time in v2004 that I and other users have experienced is the continuous, heavy access to the HDD after entering login details (which is why some have suggested switching to an SSD). Pinning down why this happens in v2004 but not in earlier versions has been the challenge. The NoDriveTypeAutoRun fix has worked on my machine but I don’t know why.

Editing the registry can indeed be dangerous which is one reason I included the link to Microsoft’s autoplay-reg documentation, not least to provide some insurance if I made a typo in my post.

And a definite thank you for the link to Mark Russinnovich’s autoruns tool.