Category Archives: Operating Systems

Operating Systems general commands and issue fixes cover in Linux , Windows, Solaris, Unix , HP-UX etc.

Taskkill Error Access denied

Taskkill Error Access denied

1. Open the Command prompt window with Administrator right.

First check Command prompt is open with administrator right with right click on it.

2. Check with the process user from which it’s running.

tasklist /V

-- Output in Excel Sheet
tasklist /V /FO CSV > E:\output.csv

Output Sample:
"oracle.exe","10124","Services","0","404,584 K","Unknown","NT AUTHORITY\SYSTEM","0:18:22","N/A"
"conhost.exe","7716","Services","0","500 K","Unknown","NT AUTHORITY\SYSTEM","0:00:00","N/A"

3. Try to kill it.

C:\Users\e3019447>taskkill /F /PID 10124
ERROR: The process with PID 10124 could not be terminated.
Reason: Access is denied.

SUCCESS: The process with PID 10124 has been terminated.




wmic process where name='oracle.exe’ delete

Different Syntax provided by Microsoft to use the Commands:


TASKKILL /IM notepad.exe
TASKKILL /PID 1230 /PID 1241 /PID 1253 /T
TASKKILL /F /IM cmd.exe /T
TASKKILL /F /FI "PID ge 1000" /FI "WINDOWTITLE ne untitle*"
TASKKILL /S system /U AMERIFIRST\tron /FI "USERNAME ne NT*" /IM oracle.exe
TASKKILL /S system /U username /P password /FI "IMAGENAME eq note*"


TASKLIST /M notepad.exe
TASKLIST /S system /U domain\username /FO CSV /NH
TASKLIST /S system /U username /P password /FO TABLE /NH


Configure yum manually on Oracle Linux Platform from Media

Configure yum manually on Oracle Linux Platform from Media

I am using Oracle Virtual box in which i installed oracle Linux platform.

Following are steps to configure yum manually through Media or ISO image:

Step 1: Transfer the complete iso image of Linux to you local drive.
Note: I am using linux 7.4 so making naming conventions as 7.4 for all folder below. So change according to your need.

mkdir /ISOs
cp /media/USB_Sticks/Linux7-4.iso /ISOs

Step 2. Create Folder for the mounting the DVD image on it:

mkdir -p /var/OSimage/OL7.4_x86_64

mount -o loop,ro /ISOs/Linux7-4.iso /var/OSimage/OL7.4_x86_64


Step 3: On Restart, we need to fire command again in step 2. Avoid it make an entry in /etc/fstab

vi /etc/fstab
-- Insert entry into file /etc/fstab
/ISOs/Linux7-4.iso /var/OSimage/OL7.4_x86_64 iso9660 loop,ro 0 0

Step 4: In /etc/yum.repos.d directory, edit the existing file present public-yum-ol74.repo and disable all entries by setting enabled=0.

vi public-yum-ol74.repo
-- Make all the enabled parameter to value 0

Step 5: Create the new entries in a new repository file

For example, /etc/yum.repos.d/OL74.repo

-- Create new file
vi /etc/yum.repos.d/OL74.repo

-- Insert following entries in file and take care of fist parameter [OL74] as naming of the file name.
name=Oracle Linux 7.4 x86_64

Step 6: Clean up the yum cache from the system.

yum clean all


Step 7: Check yum to access the repository.

yum repolist


Step 8: Verify yum is working properly.

yum list
yum install gcc

DWM process consuming CPU in windows

DWM Process consuming CPU in Windows Platform

Desktop Window Manager (dwm.exe) is a compositing window manager that renders all those pretty effects in Windows: transparent windows, live taskbar thumbnails, Flip3D, and even high resolution monitor support.

On Working on the Windows Server, I found that dwm.exe process is consuming lot of CPU and made the system in hanged State.

On checking the net regarding it. It show one service name Desktop Window Manger need to be disable but i tested on my machine first before doing on porduction Server in Windows 7, Desktop Window Manager is present in the Service list. On stop the service, it refresh the monitor display but does not have much effect in resolution.

But when tried on Windows 2012 Server, Service is not present

For Windows 7 disable steps as follows
1. Click the Start button to open the Start menu.
2. In the Windows Search box, type services and click the Services link.
3. In the Services window, search and double-click Desktop Windows Manager.
4. In the Desktop Windows Manager window, Right click to disable the service.
5. If you want this process never to start when Windows loads, change the Startup type option from Automatic to Disabled.

On Windows 2012, Service is not present you need to apply bug fix as follows:

Find the port used by process in windows

Find the port used by which process in windows

Faced one issue during configuring listener with netca utility. Its show me that port – 1521 is already in used. But when i checked the listener services is not running. Then i took backup of network folder and drop the listener on window platform. But again when try to reconfigure listener throw same error.

Then I checked with windows commands to find which application is using 1521.

1. From command prompt administrator windows run following command:


Show all running process

Check only for 1521 port:

netstat -aon | find "1521"

E:\patch_backup\deinstall>netstat -aon | find "1521"
Proto Local Address Foreign Address State Process

a : List all connections and listening ports.
O : List the owning process ID
n : List addresses and port numbers.

2. Verify the listener is running from which process id

tasklist /m ora*

Image Name PID Modules
========================= ======== ============================================
TNSLSNR.EXE 2612 oransgr11.dll, oran11.dll, oranl11.dll,
orantcp11.dll, oracore11.dll, oranls11.dll,
oraunls11.dll, orauts.dll,

3. Kill the task if needed

taskkill /PID 2612 /F


explorer.exe is using active file in windows

explorer.exe is using active file in windows

For explorer.exe is the program of windows for which is your desktop windows contains like folders, path ,start button. If explorer.exe is causing problem if you are doing any activity such as it used/lock any file then you need to stop it using by following methods:

Solution 1:
If you have all username / password for it then you logoff the system and re login it again. Then explorer will leave your locked file.

Solution 2:
you do not have username/password and using command prompt. you need to check your file who is locked from tasklist command. you got the process id from it and then you kill the process id by taskkill command as follows:

tasklist /m ocl*

Image Name     PID     Modules
============   =====   ========
explorer.exe   3136    oci.dll
vmtoolsd.exe   36108   oci.dll

You can kill the process id from command prompt

taskkill /pid 3136 /F
SUCCESS: The process with PID 3136 has been terminated.

When you kill it all your start button and explorer window is gone from screen. After that check you file is not using by any other process:

tasklist /m oci*
INFO: No tasks are running which match the specified criteria.

And to again start the explorer.exe process. you type explorer.exe on command prompt for start explorer.exe program.
Note: Sometime windows command prompt does not find the command. so, go to location c:\windows then type explorer.exe

C:\windows> explorer.exe

It will start the whole process and you get all yours windows back.
Example with snapshot
1. Check the explorer.exe file with tasklist command.


2. Kill the task with pid number, it will hide the start button from windows.


3. you will type the explorer.exe then it will show you again start button



ddlhost.exe is active file on windows

ddlhost.exe is active file on windows

We need to find out the which services is using the ddlhost.exe

Issue faced:
On application upgrade my application is hanged due to one of my application file is accessed by ddlhost.exe.

tasklist /m oci*

E:\13423278>tasklist /m oci*

Image Name    PID    Modules
============  =====  ==========
explorer.exe  3136   oci.dll
vmtoolsd.exe  36108  oci.dll
dllhost.exe   8836   oci.dll

E:\application>taskkill /pid 8836 /F
SUCCESS: The process with PID 8836 has been terminated.

E:\13423278>tasklist /m oci*

CHCP on command prompt for accept different languages

CHCP is setting active code page on the command prompt to display different language or accept different language temporary

Displays or sets the active code page number.

CHCP Specifies a code page number.

Type CHCP without a parameter to display the active code page number.

274 - Brazil
275 - Brazil
442 - Bulgaria
319 - Greece
161 - Iceland
118 - Macedonia, Serbia, and Montenegro
333 - Romania
441 - Russian
437 - United States
850 - Multilingual (Latin I)
852 - Slavic/Eastern European
860 - Portuguese
863 - Canadian-French
865 - Nordic
850 - Multilingual (Latin I)
852 - Slavic/Eastern European
857 - Turkish
861 - Greek
437 - United States
850 - Multilingual (Latin I)
852 - Slavic/Eastern European
855 - Cyrillic I
866 - Russian (Cyrillic II)
861 - Icelandic
866 - Russian
869 - Modern Greek
1252 - West European Latin
65000 - UTF-7 *
65001 - UTF-8 *