What does the "autocheck" in the default data of the registry value HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\bootexecute (Data is: autocheck autochk *) do? There's no autocheck.exe on a current (checked XP, Win7, Vista) standard Windows install, so it can't be launching an executable(?) I know what autochk does.

5 Answers 5


It's an arbitrary name associated with the boot-time command autochk *.

The BootExecute value is a REG_MULTI_SZ, i.e., it can contain multiple separate strings. However, if you double-click it in the Registry Editor you will notice that the default value is not three separate strings, autocheck, autochk and * but rather a single string autocheck autochk *.

Each string in BootExecute contains an arbitrary descriptive name followed by the command to execute.


From here. "autocheck" tells windows to run "autochk *" after previous illegal shutdown :)

By default, its value is "autocheck autochk *" - this tells Windows to run Autochk on any drive whose dirty bit is set


Autochk is standard Windows native application. AFAIK, is always present in fresh install of Windows XP.

Explain from Microsoft:

The Autochk (Autochk.exe) utility is a version of Chkdsk. For more information about Autochk, see the Windows XP Professional Resource Kit. To do this, visit the following Microsoft Web site: Troubleshooting Disks and File Systems

  • Yes, that's why I'm asking about autocheck, not autochk. ;)
    – myname
    Commented Jul 22, 2012 at 12:40

Imho, this runs some internal system checks. For example, when there is a folder C:\Program\, windows warn about it (because it interfere with C:\Program Files\).

  • Not sure I understand. I just tried to create a C:\program folder and didn't get a warning on my XP. Is this internal warnings for the OS, not the user?
    – myname
    Commented Jul 22, 2012 at 10:18
  • Was seen this warning (dialog box, suggesting to rename folder to Program1) in Windows 7. And this warning appears sometimes after booting.
    – Maximus
    Commented Jul 22, 2012 at 10:23
  • Thanks! I hadn't rebooted, I see what you mean now. :) This message still appears though, when you remove autocheck from the bootexecute value.
    – myname
    Commented Jul 22, 2012 at 10:28
  • Can you check, what process shows this warning? I was lazy to do that. May be "default value" is informational for user only, and OS runs checks everytime? :)
    – Maximus
    Commented Jul 22, 2012 at 10:34
  • The popup is from explorer.exe and a procmon log shows explorer first accessing C:\program and then testing if c:\program1 exists. explorer was launched by userinit.
    – myname
    Commented Jul 22, 2012 at 10:45

Another cause example:

In my case, Check-disk (at boot) is produced from custom shutdown batch/command, so the system thinks the shutdown was "Unexpected" (not normaly shutted) and sets the disk-check. If the "dirty" disk is the windows disk(C:) the disk must be unmounted first but, as the disk is in use by the system, sets an auto chkdsk at the next boot.

Case more explanation:

I have set a "Run-on-idle-time" 'scheduled task' which after (1hour) pointed time expiration, triggers a custom CleanNShutDown.bat/cmd program. So, the program eg. starts the 'cleans', wait to finish and then shuts down (forced) the Computer. Even if I tried many shutdown switch(es) (/d) combinations (SHUTDOWN.exe /s /t 60 /f /d p:0:0 /c "PC shutting down... (in 1 minute)" or even with chkntfs /x c:) the computer keeps giving the same problem Only IF Shutting Down triggered by this program.

How to Check if a disk is pointed as "dirty":
fsutil dirty query c: ("c:" is disk letter)

Here is almost everything about: ...(thanks Maximus)

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