Performs one of the following operations on a process: checks if it exists; changes its priority; closes it; waits for it to close.

Process, SubCommand , PIDOrName, Value


SubCommand, Value
These are dependent upon each other and their usage is described below.

This parameter can be either a number (the PID) or a process name as described below. It can also be left blank to change the priority of the script itself.

PID: The Process ID, which is a number that uniquely identifies one specific process (this number is valid only during the lifetime of that process). The PID of a newly launched process can be determined via the Run command. Similarly, the PID of a window can be determined with WinGet. The Process command itself can also be used to discover a PID.

Name: The name of a process is usually the same as its executable (without path), e.g. notepad.exe or winword.exe. Since a name might match multiple running processes, only the first process will be operated upon. The name is not case sensitive.


For SubCommand, specify one of the following:


Checks whether the specified process is present.

Process, Exist , PIDOrName

Sets ErrorLevel to the Process ID (PID) if a matching process exists, or 0 otherwise. If the PIDOrName parameter is blank, the script's own PID is retrieved. An alternate, single-line method to retrieve the script's PID is PID := DllCall("GetCurrentProcessId").


Forces the first matching process to close.

Process, Close , PIDOrName

If a matching process is successfully terminated, ErrorLevel is set to its former Process ID (PID). Otherwise (there was no matching process or there was a problem terminating it), it is set to 0. Since the process will be abruptly terminated -- possibly interrupting its work at a critical point or resulting in the loss of unsaved data in its windows (if it has any) -- this method should be used only if a process cannot be closed by using WinClose on one of its windows.


Although this sub-command is not yet supported, example #4 demonstrates how to retrieve a list of processes via DllCall().


Changes the priority level of the first matching process.

Process, Priority, PIDOrName, Level

Changes the priority (as seen in Windows Task Manager) of the first matching process to Level and sets ErrorLevel to its Process ID (PID). If the PIDOrName parameter is blank, the script's own priority will be changed. If there is no matching process or there was a problem changing its priority, ErrorLevel is set to 0.

Level should be one of the following letters or words: L (or Low), B (or BelowNormal), N (or Normal), A (or AboveNormal), H (or High), R (or Realtime). Note: Any process not designed to run at Realtime priority might reduce system stability if set to that level.


Waits for the specified process to exist.

Process, Wait, PIDOrName , Timeout

Specify for Timeout the number of seconds (can contain a decimal point) to wait before timing out. If Timeout is omitted, the sub-command will wait indefinitely. If a matching process is discovered, ErrorLevel is set to its Process ID (PID). If the sub-command times out, ErrorLevel is set to 0.


Waits for all matching processes to close.

Process, WaitClose, PIDOrName , Timeout

Specify for Timeout the number of seconds (can contain a decimal point) to wait before timing out. If Timeout is omitted, the sub-command will wait indefinitely. If all matching processes are closed, ErrorLevel is set to 0. If the sub-command times out, ErrorLevel is set to the Process ID (PID) of the first matching process that still exists.


ErrorLevel is set to 0 if a sub-command failed or timed out. Otherwise, it is set to a Process ID (PID). See the sub-commands above for details.


For the sub-commands Wait and WaitClose: Processes are checked every 100 milliseconds; the moment the condition is satisfied, the sub-command stops waiting. In other words, rather than waiting for the timeout to expire, it immediately sets ErrorLevel as described above, then continues execution of the script. Also, while the sub-command is in a waiting state, new threads can be launched via hotkey, custom menu item, or timer.

Run, WinGet, WinClose, WinKill, WinWait, WinWaitClose, WinExist()


Launches Notepad, sets its priority to "High" and reports its current PID.

Run notepad.exe,,, NewPID
Process, Priority, %NewPID%, High
MsgBox The newly launched Notepad's PID is %NewPID%.

Waits up to 5.5 seconds for Notepad to appear. If Notepad appears within this number of seconds, its priority is set to "Low" and the script's own priority is set to "High". After that, Notepad will be closed and a message box will be shown if it did not close within 5 seconds.

Process, Wait, notepad.exe, 5.5
NewPID := ErrorLevel  ; Save the value immediately since ErrorLevel is often changed.
if not NewPID
    MsgBox The specified process did not appear within 5.5 seconds.
; Otherwise:
MsgBox A matching process has appeared (Process ID is %NewPID%).
Process, Priority, %NewPID%, Low
Process, Priority,, High  ; Have the script set itself to high priority.
WinClose Untitled - Notepad
Process, WaitClose, %NewPID%, 5
if ErrorLevel ; The PID still exists.
    MsgBox The process did not close within 5 seconds.

Press a hotkey to change the priority of the active window's process.

#z:: ; Win+Z hotkey
WinGet, active_pid, PID, A
WinGetTitle, active_title, A
Gui, 5:Add, Text,, Press ESCAPE to cancel, or double-click a new`npriority level for the following window:`n%active_title%
Gui, 5:Add, ListBox, vMyListBox gMyListBox r5, Normal|High|Low|BelowNormal|AboveNormal
Gui, 5:Add, Button, default, OK
Gui, 5:Show,, Set Priority

Gui, Destroy

if (A_GuiEvent != "DoubleClick")
; else fall through to the next label:
GuiControlGet, MyListBox
Gui, Destroy
Process, Priority, %active_pid%, %MyListBox%
if ErrorLevel
    MsgBox Success: Its priority was changed to "%MyListBox%".
    MsgBox Error: Its priority could not be changed to "%MyListBox%".

Retrieves a list of running processes via DllCall() then shows them in a message box.

d := "  |  "  ; string separator
s := 4096  ; size of buffers and arrays (4 KB)

Process, Exist  ; Sets ErrorLevel to the PID of this running script.
; Get the handle of this script with PROCESS_QUERY_INFORMATION (0x0400):
h := DllCall("OpenProcess", "UInt", 0x0400, "Int", false, "UInt", ErrorLevel, "Ptr")
; Open an adjustable access token with this process (TOKEN_ADJUST_PRIVILEGES = 32):
DllCall("Advapi32.dll\OpenProcessToken", "Ptr", h, "UInt", 32, "PtrP", t)
VarSetCapacity(ti, 16, 0)  ; structure of privileges
NumPut(1, ti, 0, "UInt")  ; one entry in the privileges array...
; Retrieves the locally unique identifier of the debug privilege:
DllCall("Advapi32.dll\LookupPrivilegeValue", "Ptr", 0, "Str", "SeDebugPrivilege", "Int64P", luid)
NumPut(luid, ti, 4, "Int64")
NumPut(2, ti, 12, "UInt")  ; Enable this privilege: SE_PRIVILEGE_ENABLED = 2
; Update the privileges of this process with the new access token:
r := DllCall("Advapi32.dll\AdjustTokenPrivileges", "Ptr", t, "Int", false, "Ptr", &ti, "UInt", 0, "Ptr", 0, "Ptr", 0)
DllCall("CloseHandle", "Ptr", t)  ; Close this access token handle to save memory.
DllCall("CloseHandle", "Ptr", h)  ; Close this process handle to save memory.

hModule := DllCall("LoadLibrary", "Str", "Psapi.dll")  ; Increase performance by preloading the library.
s := VarSetCapacity(a, s)  ; An array that receives the list of process identifiers:
c := 0  ; counter for process idendifiers
DllCall("Psapi.dll\EnumProcesses", "Ptr", &a, "UInt", s, "UIntP", r)
Loop, % r // 4  ; Parse array for identifiers as DWORDs (32 bits):
    id := NumGet(a, A_Index * 4, "UInt")
   ; Open process with: PROCESS_VM_READ (0x0010) | PROCESS_QUERY_INFORMATION (0x0400)
    h := DllCall("OpenProcess", "UInt", 0x0010 | 0x0400, "Int", false, "UInt", id, "Ptr")
    if !h
    VarSetCapacity(n, s, 0)  ; a buffer that receives the base name of the module:
    e := DllCall("Psapi.dll\GetModuleBaseName", "Ptr", h, "Ptr", 0, "Str", n, "UInt", A_IsUnicode ? s//2 : s)
    if !e    ; fall-back method for 64-bit processes when in 32-bit mode:
        if e := DllCall("Psapi.dll\GetProcessImageFileName", "Ptr", h, "Str", n, "UInt", A_IsUnicode ? s//2 : s)
            SplitPath n, n
    DllCall("CloseHandle", "Ptr", h)  ; close process handle to save memory
    if (n && e)  ; if image is not null add to list:
        l .= n . d, c++
DllCall("FreeLibrary", "Ptr", hModule)  ; Unload the library to free memory.
;Sort, l, C  ; Uncomment this line to sort the list alphabetically.
MsgBox, 0, %c% Processes, %l%

Retrieves a list of running processes via COM.

Gui, Add, ListView, x2 y0 w400 h500, Process Name|Command Line
for proc in ComObjGet("winmgmts:").ExecQuery("Select * from Win32_Process")
    LV_Add("", proc.Name, proc.CommandLine)
Gui, Show,, Process List

; Win32_Process: