642

One thing that annoys me no end about Windows is the old sharing violation error. Often you can't identify what's holding it open. Usually it's just an editor or explorer just pointing to a relevant directory but sometimes I've had to resort to rebooting my machine.

Any suggestions on how to find the culprit?

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  • 21
    You would think that after all this time, the Windows guys would give us a way to do this easily from within Explorer. I wonder why this hasn't happened?
    – user1804
    May 5, 2009 at 0:19
  • 12
    I find that Explorer is very often the problem process that is holding onto a file for no obvious reason.
    – Eddie
    May 8, 2009 at 15:49
  • I know this doesn't help you much, but I think I remembered that this was a planned feature of the next Windows release after vista and 2008 server. or maybe it's a WinFS thing. not sure where i read that...
    – Kip
    May 30, 2009 at 0:00
  • see my answer on superuser here, in summary OpenedFilesView still works in 2019
    – Vijay
    Sep 22, 2019 at 12:42
  • 2
    2021... Issue still exists in Windows 10. Randomly got to this question on unrelated search. When I stumble upon this problem with something holding the file, it's often explorer.exe as Eddie suggested, I kill explorer.exe from Task Manager, this fixes the issue and disables almost all UI. Now you need to restart your explorer.exe, I just press Win+R and type explorer.exe there and press enter, it starts explorer.exe and life is good again :).
    – KulaGGin
    Mar 7, 2021 at 7:14

18 Answers 18

519

I've had success with Sysinternals Process Explorer. With this, you can search to find what process(es) have a file open, and you can use it to close the handle(s) if you want. Of course, it is safer to close the whole process. Exercise caution and judgement.

To find a specific file, use the menu option Find->Find Handle or DLL... Type in part of the path to the file. The list of processes will appear below.

If you prefer command line, Sysinternals suite includes command line tool Handle, that lists open handles.

Examples

  • c:\Program Files\SysinternalsSuite>handle.exe |findstr /i "e:\" (finds all files opened from drive e:\"
  • c:\Program Files\SysinternalsSuite>handle.exe |findstr /i "file-or-path-in-question"
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  • 22
    You can close the handle, but keep in mind, you're pulling the rug out from under an application, results will be unpredictable at best.
    – WaldenL
    May 1, 2009 at 21:57
  • 13
    @Walden: Absolutely. YMMV. With WinXP, I've many times had Explorer open a handle for no obvious reason and refuse to close it. When this happens on a file you need to delete, you have the choice of forcing the handle closed, or rebooting. So far, having done this dozens of times, I have suffered no ill effect. As with any advanced tool, use with caution and judgment.
    – Eddie
    May 1, 2009 at 22:32
  • 6
    Closing the handles can cause the app to re-use the handle on another file, causing corruption - see Jeff's answer below: serverfault.com/a/15695/79266 ... much safer to kill the application holding the file open, if you don't want to reboot.
    – RichVel
    Mar 30, 2012 at 8:32
  • 14
    For explorer, btw, hold ctrl-shift and right-click a blank area of the start menu, and you'll get "Exit Explorer" - ps, not quite Jeff's answer..
    – Mark Sowul
    Apr 2, 2012 at 18:56
  • 4
    It should be noted that ProcessExplorer must be run as Administrator or it may not able to see files open by system processes.
    – end-user
    May 4, 2017 at 10:22
313

You can use the Resource Monitor for this which comes built-in with Windows 7, 8, and 10.

  1. Open Resource Monitor, which can be found
    • By searching for Resource Monitor or resmon.exe in the start menu, or
    • As a button on the Performance tab in your Task Manager
  2. Go to the CPU tab
  3. Use the search field in the Associated Handles section
    • See blue arrow in screen shot below

When you've found the handle, you can identify the process by looking at the Image and/or PID column.

You can then try to close the application as you normally would, or, if that's not possible, just right-click the handle and kill the process directly from there. Easy peasy!

Resource Monitor screenshot

Copied from my original answer: https://superuser.com/a/643312/62

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  • 4
    It's worth noting that it can be hard to find this program on Windows 8 - a search for 'resmon.exe' should locate it.
    – Kylotan
    Feb 12, 2015 at 10:27
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    @Kylotan, Stop wasting time searching. Just run resmon directly from cmd
    – Pacerier
    Jun 8, 2015 at 20:27
  • 1
    @Pacerier: Nice. I'm not used to things being in the Windows path.
    – Kylotan
    Jun 9, 2015 at 8:32
  • 6
    Still valid in Windows 10 and can be found by using the "Open Resource Monitor" button inside Task Manager -> Performance tab. Feb 10, 2017 at 20:48
  • 1
    @cletus This should be the accepted answer as it doesn't require third-party software
    – Wizard79
    Oct 19, 2023 at 8:07
106

Just be very careful with closing handles; it's even more dangerous than you'd think, because of handle recycling - if you close the file handle, and the program opens something else, that original file handle you closed may be reused for that "something else." And now guess what happens if the program continues, thinking it is working on the file (whose handle you closed), when in fact that file handle is now pointing to something else.

see Raymond Chen's post on this topic

Suppose a search index service has a file open for indexing but has gotten stuck temporarily and you want to delete the file, so you (unwisely) force the handle closed. The search index service opens its log file in order to record some information, and the handle to the deleted file is recycled as the handle to the log file. The stuck operation finally completes, and the search index service finally gets around to closing that handle it had open, but it ends up unwittingly closing the log file handle.

The search index service opens another file, say a configuration file for writing so it can update some persistent state. The handle for the log file gets recycled as the handle for the configuration file. The search index service wants to log some information, so it writes to its log file. Unfortunately, the log file handle was closed and the handle reused for its configuration file. The logged information goes into the configuration file, corrupting it.

Meanwhile, another handle you forced closed was reused as a mutex handle, which is used to help prevent data from being corrupted. When the original file handle is closed, the mutex handle is closed and the protections against data corruption are lost. The longer the service runs, the more corrupted its indexes become. Eventually, somebody notices the index is returning incorrect results. And when you try to restart the service, it fails because its configuration files have been corrupted.

You report the problem to the company that makes the search index service and they determine that the index has been corrupted, the log file has mysteriously stopped logging, and the configuration file was overwritten with garbage. Some poor technician is assigned the hopeless task of figuring out why the service corrupts its indexes and configuration files, unaware that the source of the corruption is that you forced a handle closed.

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  • 15
    important warning, this should go nearer the top - a reboot is probably better than a silently corrupted file.
    – RichVel
    Mar 30, 2012 at 8:27
  • 12
    +1 This will certainly make me think twice about forcing handles closed! It seems strange to me that Windows would immediately re-use the number of a closed handle, rather than continuing to increment the number and only wrapping around when necessary. That would at least greatly reduce the chances of this problem happening.
    – EM0
    Dec 8, 2014 at 20:49
  • 3
    @RichVel Terminating the culprit process is probably better than a complete reboot. May 5, 2017 at 8:21
  • 3
    This is a very important warning, but doesn't answer the question How do you find what process is holding a file open in Windows?
    – user421077
    Jul 26, 2017 at 14:56
  • 1
    I don't think it is a security vulnerability. The process already has access to whatever it had access to. Raymond describes this situation as "It rather involved being on the other side of this airtight hatchway" -- a recent example: devblogs.microsoft.com/oldnewthing/20200203-00/?p=103391
    – Mark Sowul
    Mar 3, 2020 at 19:16
99

If you are having enough privileges, try the openfiles command.

You might have to enable listing of localy opened files by running openfiles /local on and rebooting.

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  • 10
    +1 for a builtin command, although I personally use ProcessExplorer for this most of the time.
    – RBerteig
    May 6, 2009 at 2:04
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    ERROR: The target system must be running a 32 bit OS.
    – Bozojoe
    Oct 24, 2012 at 17:29
  • 5
    doesn't work for 64 OS!
    – user35861
    Sep 30, 2014 at 15:14
  • 15
    This looks to be working for Windows 2012R2 64bit, but you need to enable the "open local tracking" service by running openfiles /local on and restarting. This makes this feature not very useful.
    – Guss
    Aug 30, 2015 at 13:06
  • 1
    C:\WINDOWS\system32>openfiles /local on SUCCESS: The system global flag 'maintain objects list' is enabled. This will take effect after the system is restarted. Oh great, that was helpful thanks.
    – Andrew
    Oct 28, 2017 at 7:41
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I've used Handle with success to find such processes in the past.

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    I use this tool all the time. If I can't eject a USB drive, I just type "handle H:" (or whatever the drive letter). Best of all, you can use it to force close handles. May 2, 2009 at 7:02
  • I've been told so many times at SO that link-only answers are discouraged. With this here now I'm one of those purists. ;) Sep 12, 2021 at 12:16
12

Lockhunter (http://lockhunter.com/) works on 32 and 64bit systems.

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  • It's also available from that file's context menu in Windows Explorer.
    – user61849
    Jun 26, 2019 at 22:01
  • 1
    In my case none of other answers worked, also Lockhunter when I typed in the file name did not find any process locking it, but the context menu option worked! Thanks!
    – raj
    Feb 25, 2021 at 13:14
  • I've been told so many times at SO that link-only answers are discouraged. With this here now I'm one of those purists; and even a double one. ;) Sep 12, 2021 at 12:17
  • @GeroldBroser this was one of the best answers I've seen here and it's "link only". You might wanna rethink your last statement lol
    – Gaspa79
    Dec 2, 2021 at 17:26
  • @Gaspa79 My last statement is the "double one". And this is still true. See my comment to the answer above(AToW). :) Dec 2, 2021 at 20:06
8

Just to clarify, this is more likely to be a result of misbehaving 3rd party apps not using the CreateFile API call correctly than it is to be anything in Windows itself. Perhaps it's a consequence of the design of CreateFile, but done is done and we can't go back.

Basically when opening a file in a Windows program you have the option to specify a flag that allows shared access. If you don't specify the flag, the program takes exclusive access of the file.

Now, if Explorer seems to be the culprit here, it may be the case that that's just on the surface, and that the true culprit is something that installs a shell extension that opens all files in a folder for it's own purposes but is either too gung-ho in doing so, or that doesn't clean up properly after itself. Symantec AV is something I've seen doing this before, and I wouldn't be surprised if other AV programs were also to blame. Source control plug-ins may also be at fault.

So not really an answer, but just some advice to not always blame Windows for what may be a badly written 3rd party program (something that can also happen on any other OS which has implicit file locking, but any unix based OS has shared access by default).

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    I won't blame a 3rd party app on the fact that my windows explorer always locks Thumbs.db files in its working directory, but does not always unlock it when I switch working directory. At least they are unlocked when I close the window, I don't have to kill ALL explorers...
    – Alexander
    Mar 7, 2014 at 7:32
  • @Darth, Are you a marketer from Microsoft?
    – Pacerier
    Jun 8, 2015 at 20:29
6

On a remote server, when you're checking on a network share, something as simple as the Computer Management console can display this information and close the file.

2
  • Exactly, why are there such complicated answers ? Aug 31, 2016 at 2:52
  • The question is not in the context of a network share being held open by another remote user on the network, but of a file or folder being held open by a process on the local machine.
    – JakeRobb
    Nov 16, 2023 at 15:19
6

Apropos Explorer holding a file open: "When this happens on a file you need to delete, you have the choice of forcing the handle closed, or rebooting."

You can just end Explorer.

If this is a one-time thing (Explorer does not normally hold this file open) then I would guess logging off and logging back on will do the trick.

Otherwise, kill the desktop Explorer process and do what you want while it's gone. First start a copy of cmd.exe (you need a UI to do your intended cleanup). Make sure there are no non-desktop Explorers running. Then kill the last Explorer with, e.g., Task Manager. Do what you want in the command prompt. Finally, run Explorer from the command prompt, and it will become the desktop.

I'd guess there may be some residual unpleasantness if some systray programs can't deal with the shell restarting.

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  • 1
    This is much safer than closing the handle, and less disruptive than rebooting. Applies to other programs too - I often find a Microsoft Office program holds locks on files even after I've closed them.
    – RichVel
    Mar 30, 2012 at 8:30
6

Who Lock Me works well and keeps people amused with the name!

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  • Doesn't work in 64-bit Windows 8 and 10.
    – rustyx
    Aug 15, 2016 at 7:38
  • I've been told so many times at SO that link-only answers are discouraged. With this here now I'm one of those purists; and even a triple one. ;) Sep 12, 2021 at 12:19
5

Files can be locked by local processes (unlocker is the tool to use) and by file access that comes in through shares.

There is a built-in function in Windows that shows you what files on the local computer are open/locked by remote computer (which has the file open through a file share):

* Select "Manage Computer" (Open "Computer Management")
* click "Shared Folders"
* choose "Open Files"

There you can even close the file forcefully.

4

With Process Hacker you can identify what processes are holding your files easily:

Find Handles or DLLs

3

There is NirSoft's Opened Files View as well.

Screenshot

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    Personally I like this better than Process Explorer for this specific tasks. Feb 25, 2013 at 19:38
  • I've been told so many times at SO that link-only answers are discouraged. With this here now I'm one of those purists; and even a quadruple one. ;) Sep 12, 2021 at 12:20
  • @GeroldBroser: You seem to have a wrong impression of "link-only answer". It does not mean that the answer contains a link which is relevant to the entire answer. It means that if the link cannot be followed (e.g. you look at a screenshot of the answer) that all information is lost. That isn't the case here, with no links this is still a valid answer (and already was in the version you commented on, as the text alone was meaningful, although the image definitely improved the answer).
    – Ben Voigt
    Mar 30, 2022 at 20:26
3

There have new PowerToys available from Microsoft.

File Locksmith utility for Windows | Microsoft Learn
https://learn.microsoft.com/en-us/windows/powertoys/file-locksmith

After installing PowerToys, right-click on one or more selected files in File Explorer, and then select What's using this file? from the menu.

2

The above upvoted answers cover situations where a program process is holding the file handle open, which (fortunately) is most of the time - however in some cases (as is occurring on this system at the moment), the system itself holds a file handle open.

You can identify this situation by following the instructions to find the file handle holding process with process explorer above, and noting that the process name is listed as 'system', or by following the the instructions using resource monitor and noting that no image is shown having a filehandle open on your file of interest (Although obviously something does as you can't edit/delete etc the file).

If that happens, your option (so far as I'm aware) is to restart - or forget about doing anything with that file.

2

You can also do it programmatically by leveraging on the NTDLL/KERNEL32 Windows API. E.g. have a look at the following code in Python:

import ctypes
from ctypes import wintypes

path = r"C:\temp\test.txt"

# -----------------------------------------------------------------------------
# generic strings and constants
# -----------------------------------------------------------------------------

ntdll = ctypes.WinDLL('ntdll')
kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)

NTSTATUS = wintypes.LONG

INVALID_HANDLE_VALUE = wintypes.HANDLE(-1).value
FILE_READ_ATTRIBUTES = 0x80
FILE_SHARE_READ = 1
OPEN_EXISTING = 3
FILE_FLAG_BACKUP_SEMANTICS = 0x02000000

FILE_INFORMATION_CLASS = wintypes.ULONG
FileProcessIdsUsingFileInformation = 47

LPSECURITY_ATTRIBUTES = wintypes.LPVOID
ULONG_PTR = wintypes.WPARAM


# -----------------------------------------------------------------------------
# create handle on concerned file with dwDesiredAccess == FILE_READ_ATTRIBUTES
# -----------------------------------------------------------------------------

kernel32.CreateFileW.restype = wintypes.HANDLE
kernel32.CreateFileW.argtypes = (
    wintypes.LPCWSTR,      # In     lpFileName
    wintypes.DWORD,        # In     dwDesiredAccess
    wintypes.DWORD,        # In     dwShareMode
    LPSECURITY_ATTRIBUTES,  # In_opt lpSecurityAttributes
    wintypes.DWORD,        # In     dwCreationDisposition
    wintypes.DWORD,        # In     dwFlagsAndAttributes
    wintypes.HANDLE)       # In_opt hTemplateFile
hFile = kernel32.CreateFileW(
    path, FILE_READ_ATTRIBUTES, FILE_SHARE_READ, None, OPEN_EXISTING,
    FILE_FLAG_BACKUP_SEMANTICS, None)
if hFile == INVALID_HANDLE_VALUE:
    raise ctypes.WinError(ctypes.get_last_error())


# -----------------------------------------------------------------------------
# prepare data types for system call
# -----------------------------------------------------------------------------

class IO_STATUS_BLOCK(ctypes.Structure):
    class _STATUS(ctypes.Union):
        _fields_ = (('Status', NTSTATUS),
                    ('Pointer', wintypes.LPVOID))
    _anonymous_ = '_Status',
    _fields_ = (('_Status', _STATUS),
                ('Information', ULONG_PTR))


iosb = IO_STATUS_BLOCK()


class FILE_PROCESS_IDS_USING_FILE_INFORMATION(ctypes.Structure):
    _fields_ = (('NumberOfProcessIdsInList', wintypes.LARGE_INTEGER),
                ('ProcessIdList', wintypes.LARGE_INTEGER * 64))


info = FILE_PROCESS_IDS_USING_FILE_INFORMATION()

PIO_STATUS_BLOCK = ctypes.POINTER(IO_STATUS_BLOCK)
ntdll.NtQueryInformationFile.restype = NTSTATUS
ntdll.NtQueryInformationFile.argtypes = (
    wintypes.HANDLE,        # In  FileHandle
    PIO_STATUS_BLOCK,       # Out IoStatusBlock
    wintypes.LPVOID,        # Out FileInformation
    wintypes.ULONG,         # In  Length
    FILE_INFORMATION_CLASS)  # In  FileInformationClass

# -----------------------------------------------------------------------------
# system call to retrieve list of PIDs currently using the file
# -----------------------------------------------------------------------------
status = ntdll.NtQueryInformationFile(hFile, ctypes.byref(iosb),
                                      ctypes.byref(info),
                                      ctypes.sizeof(info),
                                      FileProcessIdsUsingFileInformation)
pidList = info.ProcessIdList[0:info.NumberOfProcessIdsInList]
print(pidList)
1

I got turned on to the Free Extended Task Manager a while ago by Jeremy Zawodny's blog, and it's great for tracking down further info on processes too. +1 for Process Explorer as above, too, especially for killing processes that the standard Task Manager won't end.

0

There is a tool FILEMON and shows open files and handles. Its hard to keep up with its display if you watch it live, it does so quickly. But you can stop it from displaying live and you can watch all file open/write activity. Now owned by Microsoft but originally by Sysinternals

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