Video Tutorial


Video is available in 1080p. Please view in full screen for optimal viewing experience.

What is Boot Optimization?

Boot Optimization, not to be confused with "boot optimization tools" is a newly revised feature of the windows defrag utility that improves the overall startup time of a machine.

How does it work?

This feature works by reducing the overall amount of time your machine spends locating non-contiguous boot files and startup items during the boot process. By ordering these files in a contiguous manner, your disk heads spend less time seeking and more time accessing resulting in a much faster boot time.

How To Enable Boot Optimization

1. Install Superfetch

Superfetch is needed to rebuild the Layout.ini file for boot optimization to cache startup applications AND boot files.

You can download Superfetch via the R2 Conv GUI here: viewtopic.php?f=21&t=1460

Thanks to neige for the upload.

2. Download the BootOptimize.reg attachment below to enable the Boot Optimization feature. Note that you have only enabled the function and not actually used it yet!

3. Open Command Prompt. (Click start, type in cmd, and choose "Run as Administrator")

In command prompt type in the following command:

sc start defragsvc

This will start the Disk Defragmentation service.

Next type in the following command:

rundll32.exe advapi32.dll,ProcessIdleTasks

NOTE: This process takes roughly 10-15 minutes to complete!

This command will build the Layout.ini located in C:\Windows\Prefetch. It will build a "database" of optimized files that is passed on to the disk defrag service will which complete the process.

According to our good friend Wikipedia:

"Every three days, when the machine is idle, a list of files and directories that are referenced during the boot process and application startups is created. This list is stored in Layout.ini in the Prefetch directory, and is subsequently passed to the Disk Defragmenter, instructing it to place all the files in sequential order on the physical hard drive, which will further improve startup performance, as Windows will spend less time waiting for the hard drive's heads to move to the relevant data. Alternatively, running "Defrag.exe %systemdrive% -b" from the command line forces a defragmentation of the prefetcher files without requiring a full Defragmentation"

TIP: Use Resource Monitor to track when this command has completed. You can tell when this command is complete based on the amount of disk thrashing in Resource Monitor. For example when you run the command you will see your Disk usage go up to say "10 MB/sec" and it will stay in MB range until it completes. When it completes your disk usage will go down to the KB range, signifying to you that the process has been completed.

To open Resource Monitor, click on Start and type in "Resource Monitor". Then in Resource Monitor ensure that the "overview" tab is selected. On the right-side, look for "Disk". You should see the current disk activity in KB or MB/sec. For example 100 KB/sec.


4. While still in command prompt, type in the following command:

defrag C: /b

Assuming C: is the drive letter of your operating system. If it is E: for example you would type in defrag E: /b

You will receive a message saying "Invoking Boot Optimization..."

The process should take 10-20 minutes depending on your hardware specs and speed of your hard disk. When you are able to type in commands into command prompt the process is complete.

Your computer will need to be restarted 6 times (not joking) in total for Windows to successfully learn the status of your boot files and build a sufficient database of prefetched files. If completed successfully after a few reboots you should notice a drastic reduce in boot time! You should notice a change by the 3rd reboot.

Hi halladayrules, need Superfetch service ?

You might I'm not sure though. It's a separate feature of 7 but im not sure if it utilizes the caching feature of Superfetch or uses another utility altogether.

I made some tests and need Superfetch service, but look error:



Lacks some register, create in:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Dfrg\BootOptimizeFunction
NAME - TYPE - DATA
Enable - REG_SZ - Y
LcnEndLocation - REG_SZ -
LcnStartLocation - REG_SZ -

Look, now:


Boot time:
68s to 45s -> normal defragmentation
45s to 38s -> Superfetch + boot optimization + bare-bone services

Ty halladayrules, for good found

I got same 0x89000017 error code, you just need to rerun the "Rundll32.exe advapi32.dll,ProcessIdleTasks"
command once more and then "defrag C: /b" again and it will work.

Nice finding again, halladayrules! You keep amazing me!

Added a link to your well-explaining steps to the win2008r2workstation.com main page under step 19 so more people will be able to find it.

I have recently discovered that Superfetch is required to rebuild the Layout.ini file which the defrag service uses to optimize your boot files AND startup apps.

I am getting the following error after trying the above steps:



My RegKey looks as so after running the defrag c: /b



Anyone have any ideas?

Rerun "Rundll32.exe advapi32.dll,ProcessIdleTasks" and try again. It should work.
The boot optimization does not work on SSDs from what I can gather, if you have an SSD it will not work.

Also try this:

Right-click on "BootOptimizeFunction" key and go to permissions. Add your username and give yourself full control. Exit command prompt. Then re-enter it again.

Type in

Rundll32.exe advapi32.dll,ProcessIdleTasks
defrag C: /b

try once again if it doesn't work the first time.

It looks like all I was missing was the prefetch function. It's working great now, no errors.