I'm trying to delete an executable, but it fails with the error Access is denied even adding /F to force it as del /F system.exe. I'm using an elevated Command Prompt.

Attempting to delete the file through Windows Explorer yields the following:

error message

I went into the Security properties of the executable. Highlighted are the odd permission entries which may be stopping me from deleting this file:

advanced security settings

Originally, it did not let me delete the entries; the option was greyed out. I performed takeown /F C:\ProgramData\994146\system.exe, deleted the entries, added ones which gave me full permissions, and closed the dialogue box. The error persisted. When I reopened the Advanced Security Settings, the entries were back.

The parent folder of system.exe, 994146, is completely invisible in ProgramData. I have "show hidden files" on ProgramData. I had to manually type the path in Windows Explorer's address bar. I am also not sure how to edit the properties of 994146 since I can not select it in the file hierarchy.

  • you say "even" with /F it's not like /F is some powerful thing. What about something many find effective, like unlocker?(google unlocker) or any of the normal techniques one uses when they can't delete a file in windows, like using process explorer to see if any process is locking the file.. You know - techniques that people tend to find work.. Techniques that are listed whenever anybody asks how to delete a file that windows won't let you delete
    – barlop
    Aug 22 '15 at 1:08
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    And why do you write "batch delete" in the title, and then you write "I'm trying to delete an executable," . Batch is like a bat file, rather than command line. This is one command, not a batch file
    – barlop
    Aug 22 '15 at 1:11
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    If you have malware like this, you really ought to backup your data and wipe the machine. Aug 22 '15 at 2:43
  • I am curious if you "even" checked if system.exe is in task manager? (given that it showed in process explorer)
    – barlop
    Aug 22 '15 at 9:09

Put bad processes on ice:

  1. Download and run Process Explorer (from Microsoft) as Admin
  2. In the Options > VirusTotal.com menu enable Check VirusTotal.com and accept the license agreement
  3. A new column will appear titled VirusTotal with a number like 0/57. The first number indicates how many virus scanners think the process is infected. The second number indicates how many scanned the file. 0/57 would indicate a clean process while 19/57 would indicate 19 scanners think the process is bad.
  4. For any processes flagged as infected, right-click and Suspend (do not kill)
  5. Once all suspicious processes have been suspended, kill them one at a time
  6. If any new infected processes re-appear, suspend them and don't kill them
  7. Change the file permissions on your unwanted executable to regain Full Control, then delete it
  8. Once you've deleted the file, you need to immediately move into scanning your computer for malware

If this doesn't work, then break out the fire:

  1. Download and run Process Monitor (also from Microsoft) and run as Admin
  2. On the Filter menu click Filter...
  3. Create a filter condition to match your file as follows: enter image description here
  4. Click Add then OK
  5. Change the permissions on your file
  6. Review Process Monitor's output. You'll see that explorer.exe accesses the file (that's you, changing the permissions). Look for any other processes that touches the file...most likely the last process to do so. This is most likely going to be your malicious process.
  7. Use Process Explorer to suspend that process (the PID value shown by Process Monitor is also shown by Process Explorer)
  8. Try changing the permissions/deleting the file again
  • 1
    How do you know it's the only remnant? What makes you so sure there's not a rootkit that you can't even see? Aug 22 '15 at 2:47
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    @Gnomechild The large number of events in Process Monitor is normal. The fact csrss.exe is involved means you have a serious infection. You need to move into full scale malware removal efforts. You have more going on than you originally thought. Aug 22 '15 at 3:17
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    @Gnomechild That's not correct. This process is critical to Windows operation. Trust me, if something running inside (i.e. "injected") in this process is preventing you from deleting a bad file, you've got a serious infection. Act accordingly. Aug 22 '15 at 3:23
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    I am curious.. I suppose that ythe reason you suspend them first, is the reason stated here superuser.com/questions/325603/… which is that they may act as watchdogs on each other.. Considering though that if you suspended them one by one they could still act as watchdogs for each other, and that you can I suppose get around that by suspending them all at the same time.. How would that be any better than killing them all at the same time?
    – barlop
    Aug 22 '15 at 9:23
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    @barlop You're correct that this is an anti-watchdog technique. I've not enjoyed the same success by killing the processes simultaneously. It only takes a millisecond for a watchdog process to see its buddy dead and respawn it. Compared to the suspend-and-kill approach, it's tough to kill a number of process that fast. I've yet to have a process take action against suspending its buddies, but I suppose that day is coming. Aug 22 '15 at 13:36

This is my "chown.bat" (unix folks will laugh at me using that name). I've cobbled it together from various solutions... Each time one doesn't work, I add more stuff. The SetACL stuff I only discovered in 2014 or 2015. This has never failed me:

    for /r %fn in (*.*)  SetACL -on "%fn" -ot file -actn clear -clr dacl,sacl
    takeown /F * /R /D  Y
    icacls   *.* /T /C /grant YOURUSERACCOUNTNAMEHERE:(D,WDAC)
    icacls    .  /T /C /grant administrators:F System:F everyone:F

SetACL is a 3rd party utility that needs to be in your path.

  • Comment submitted as an edit: [This solution worked, thank you! However, I had to change your FOR line in 2 ways. At least on Windows 10, the %variable seems to have to be a single letter. So your "%fn" became just "%f" if that line is run at the command line. (And note that if you put those lines in a batch file, that variable has to have double % signs, as in "%%f", which is what I have above.) Finally, I needed to add "DO" before the "SetACL". See above. And many thanks again for finally getting me to where I could just delete an executable]
    – Mokubai
    Jul 6 '17 at 7:02
  • Thanks! I use TakeCommand (TCC.EXE) as a command-line, so I may have minor variances in my implementations :) It's nice to know someone went through it with a fine-tooth comb to make it more compatible to more common command-lines. I might just change my local BAT file to reflect your edits just for giggles :)
    – ClioCJS
    Jul 7 '17 at 6:52
  • Also, for TakeCommand, instead of YOURUSERACCOUNTNAMEHERE, one can get away with %_winuser% -- not sure if that works elsewhere.
    – ClioCJS
    Jul 7 '17 at 6:54

Just run:

takeown * /F /R /D  Y
icacls . /T /C /grant administrators:F System:F everyone:F
del * /s /q
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In my case, the solution to this particular problem was to run Kaspersky's TDSSKiller; it may have been a trojan.

  • 1
    It's one piece of anti malware software and no one piece of anti malware software has any magic power to eliminate absolute any trojan. I'm not necessarily suggesting using more than one, maybe one should, maybe not, but i'm just saying your claim is either extravagent or meaningless. "should completely eliminate" (what does 'should' mean. So when you run an anti malware program and it doesn't do it you scratch you head and say it should have? ) And you give no argument to support your claim either.
    – barlop
    Aug 23 '15 at 14:12

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