Home » Alerts » Symptoms, Causes and Solution of Kaspersky Anti-Virus Error 0xC21D0400

This error will reflect if you perform either incomplete installation or you download a corrupt file. So here are the symptoms and reasons of this error:


  • The active program window crashes after showing “Error 0xC21D0400″
  • While running your Kespersky antivirus installation, your system frequently crashes with Error 0xC21D0400
  • “Kaspersky Error 0Xc21D0400” is displayed on your computer screen
  • Windows runs feebly and responds with a delay to mouse or keyboard input
  • System periodically “freezes” for a few seconds often

These 0xC21D0400 error messages can appear while installing any application when Kaspersky Lab-related software program (eg. Kaspersky Anti-Virus) is running, during the Windows OS installation or Windows startup or shutdown.

Note– To troubleshoot the problem, it’s important to keep the track of when and where your 0xC21D0400 error occurred.

Kaspersky Errors


  • Corrupt download or incomplete installation of Kaspersky application
  • Corruption in Windows registry because of recent changed made by installing or uninstalling a recent Kaspersky Anti-Virus-related software
  • Virus or malware infection that has corrupted Kaspersky Anti-Virus-related program files or Windows system files
  • Another malicious program intentionally mistakenly remove Kaspersky Anti-Virus related files

Note- There may be several reasons of Runtime Errors such as “Error 0xC21D0400” so it is important that you troubleshoot every possible cause to prevent runtime Errors from recurring.

Step 1: Repair Error 0xC21D0400 Associated Registry Entries

There are two ways to edit Windows registry in order to remove error codes. Manual editing to remove the error key is not recommended if you are PC service professional. Because in case of any mistake, your machine will stop working or it may bring irreparable errors which may create irreversible damage to your operating system. It’s so critical that even one misplaced comma can prevent booting function completely.

So because of the high risk involved, it’s a better option to use a trusted registry cleaner. But if you want to repair Windows registry manually, you need to create a backup by exporting registry files related to Error 0xC21D0400 (eg. Kaspersky Anti-Virus). The instruction written tare helpful to create the backup:

  • Click the Start button.
  • Write “command” in the search box but DO NOT hit ENTER yet!
  • Now hold CTRL-Shift on your keyboard, press ENTER key.
  • You will open a permission dialog box.
  • Click Yes.
  • Now a black box will open with a blinking cursor.
  • Write “regedit” and press ENTER key.
  • Select the Error 0xC21D0400-related key (eg. Kaspersky Anti-Virus) that you want to back up in the Registry Editor.
  • Choose Export from the File menu
  • In the Save In list, select a folder where you wish to save the Kaspersky Anti-Virus backup key.
  • Now type a name for your backup file In the File Name box, like “Kaspersky Anti-Virus Backup“.
  • Select “Selected branch” in the Export Range box.
  • Now click Save.
  • Your file will be saved with a .reg file extension.
  • Now you have created a backup of your Kaspersky Anti-Virus-related registry entry.

Step 2: Conduct a Scan of Your PC

Conduct a full malware scan because there may be the possibility of any virus infection which is causing 0xC21D0400 error. Malware can’t not only cause this error, but also cause other run-time errors, damage and corrupt your important files.

Step 3: Remove all Junk Files from Your System (Temporary Files and Folders)

Over time, your PC collects junk files. These junk files may be the traces of your browsing habits or you have downloaded a malicious or incomplete file. You need to clean the junk files at regular intervals otherwise it causes Kaspersky Anti-Virus to respond slowly or display 0xC21D0400 error. Cleaning up these temporary files is the solution of problems which will dramatically speed up your computer performance.

Because of the shortcomings of the Windows Disk Cleanup (cleanmgr) tool, it’s recommended use specialized hard drive cleanup / privacy protection software to clean up your entire computer. Run it once per day to ensure that your computer remains clean, run fast, and does not show 0xC21D0400 error or such other errors related to temporary files.

Step 4: Update Your Device Drivers

Corrupt or outdated device drivers may also cause0xC21D0400 and related errors. Drivers may stop working suddenly even if yesterday they were working fine. There may be various reasons but the good thing is that you can update them and fix the Error 0xC21D0400 encountered because of drivers issues.

It’s not tough to find the exact driver for your Error 0xC21D0400 but finding related hardware device can be an extremely difficult task. Moreover, it’ll consume a lot time, may irritate you, even if you’re experienced at finding, downloading, and manually updating drivers. One more drawback of doing it manually is that you may install a wrong driver or incompatible version of the required driver which makes the situation more panic.

To avoid these complexities, it’s recommended that use a driver update tool to automate the process. The driver updater software updates all PC device drivers and creates a backup of your current drivers before applying any changes to them.

Step 5: Use Windows System Restore to “Undo” Recent System Changes

Windows System Restore allows you to undo the changes you made with your machine. It allows you to “go back in time” to fix your Error 0xC21D0400 problems. It can return your system files and program in a previous state when everything was working fine. This activity help you to avoid long troubleshooting hours and errors associated with 0xC21D0400. Plus, it does not affect your documents, pictures, or other data stored on the system.

To use System Restore (Windows XP, Vista, 7, 8, and 10):

  • Click the Start button
  • type “System Restore” In the search box and press ENTER
  • Click System Restore in the results
  • If prompted enter any administrator passwords
  • Follow the steps in the Wizard to choose a restore point
  • Finally Restore your computer

Step 6: Uninstall and Reinstall the Kaspersky Anti-Virus Software Associated with the Error

Uninstalling and reinstalling can be possible solution if your Kespersky Antivirus application shows 0xC21D0400 error or other errors related to a specific program.

Instructions for Windows 7 and Windows Vista:

  • Click the start button and open Programs and Features
  • On the right side menu, click Control Panel
  • Click Programs.
  • Click Programs and Features.
  • Under the Name column, locate Kaspersky Error 0Xc21D0400-associated program (eg. Kaspersky Anti-Virus)
  • Click on the Kaspersky Anti-Virus-associated entry
  • Now click the Uninstall button on the top menu strip
  • To complete the uninstallation of your Error 0xC21D0400-associated program, follow the on-screen directions

Instructions for Windows XP:

  • Click the start button and open Programs and Features
  • Open Control Panel
  • Click Add or Remove Programs.
  • Under the list of Currently Installed Programs, locate Kaspersky Error 0Xc21D0400-associated program (eg. Kaspersky Anti-Virus)
  • Click on the Kaspersky Anti-Virus-associated entry
  • Click the Remove button on the right side to remove its entry
  • To complete the uninstallation Kaspersky Error 0xC21D0400 associated program, follow the on-screen directions

Instructions for Windows 8:

  • To bring the Start Menu image, hover the cursor in the bottom left of your computer screen
  • To bring up the Start Context Menu, Right-Click the mouse
  • Click Programs and Features
  • Under the Name column, locate Kaspersky Error 0Xc21D0400-associated program (eg. Kaspersky Anti-Virus)
  • Click on the entries associated with the Kaspersky Anti-Virus errors
  • Click the Uninstall/Change on the top menu strip
  • To complete the uninstall 0xC21D0400- Error associated program, follow the on-screen directions

Once you successfully uninstall your Error 0xC21D0400-associated program, reinstall the program according to the instructions given by Kaspersky Lab.

Step 7: Run Windows System File Checker (“sfc /scannow”)

Windows Operating Systems include System File Checker which is a useful that allows you scan for and restore corruptions in Windows system files

Steps to run System File Checker (Windows XP, Vista, 7, 8, and 10):

  • Click the Start button
  • Write “command” in the search box… DO‘T hit ENTER yet!
  • While holding CTRL-Shift on your keyboard, press ENTER
  • Now a permission dialog box will appear
  • Click Yes
  • Now a black box with a blinking cursor will open
  • Type “sfc /scannow” and press ENTER
  • System File Checker will start scanning for 0xC21D0400 error and other system file errors (the scanning process may take some time so be patient)
  • To complete the process, follow the on-screen commands.

Step 8: Install All Available Windows Updates

Microsoft keeps on updating and improving Windows system files and it may be possible that you haven’t installed the new available update which may cause E0xC21D0400 or associated errors. Sometimes the solution of fixing run-time errors is as easy as updating Windows with the latest released Service Pack or other patch on an ongoing basis.

To check for Windows Updates (Windows XP, Vista, 7, 8, and 10), follow the instructions written below:

  • Click the Start button.
  • Write “update” into the search box and press ENTER.
  • Now the Windows Update dialog box will appear.
  • If updates are available, click the Install Updates button.

Step 9: Perform a Clean Installation of Windows

This is the final step if you’re trying to resolve your 0xC21D0400 Error issue. Reinstalling a Windows will delete everything from the computer hard drive. It’s like using a fresh system again. A clean install of Windows will remove all the traces of junk and corrupted files which accumulated over your regular use of the computer.

Note- Reinstalling Windows is a very time-consuming and advanced task in order to fix Error 0xC21D0400 problems. It’ll clean the entire Windows registry so to avoid data loss, take the backup of all your important pictures, software installers, documents, and data files.

After applying all these above written steps, you’re still facing Error 0xC21D0400 issues and other Runtime Errors problems then there may a fault in your hardware and you need to replace associated hardware creating the 0xC21D0400 error.


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