Sometimes, error 421 turn ups while Outlook is running and eventually result in Outlook crash. It happens when you are installing any application on your system. There are numerous causes due to which you encounter this error. Some of them are listed below-
- Microsoft Outlook software might be incompletely installed
- Windows registry corruption due to changes made to Microsoft related software’s
- System file or Microsoft Outlook program files get damaged due to virus attack
- Deletion of Microsoft Outlook related files by third party tool
Similarly, there are other reasons too; Here I have listed out some common troubleshooting techniques which may solve Outlook error 421.
Methods for Fixing Outlook Error 421-
Method #1: Fix Entries Linked with Error 421 in Registry
As said above, registry corruption is one of the reasons for getting error 421. It can be solved by fixing Windows registry. But, you should be careful while repairing registry because a small mistake can lead you to the huge disaster. First of all, backup part of the registry that is related to error 421. To back up, do as follows-
- Open command prompt and type regedit to open Registry Editor
- Select the Error 421-related key i.e. Microsoft Outlook which you wish to back up.
- Then go to File-> Export
- Choose the folder to save Microsoft Outlook backup key and enter name for backup
- Ensure that “Selected branch” is selected and hit Save
- Now, backup file will be saved with .reg file extension
Once you take a backup, repair your registry with trusted registry repair software or take it to the expert to manually repair it.
Method #2: Scan Computer for Malware
If you have Antivirus software on your system, then full scan your computer for virus. If it finds any, then remove them. But, make sure that you are using an updated and reliable Antivirus software.
Method #3: Remove System Junk Files
Junk files accumulate on your system due to frequent computer use and internet surfing. These junk files slow down your computer performance and also result in Outlook error 421. Hence, clean up your system using Disk Cleanup- a Windows built-in tool.
- Open command prompt and type “cleanmgr”
- It starts Disk Cleanup which calculates occupied disk space that you can reclaim
- It shows the sequence of checkboxes. Check and select necessary field to clean
- At last, click OK.
Method #4: Use Windows System File Checker
System File checker helps to fix system errors. To run this tool, follow the steps mentioned below-
- Open command prompt and type “sfc /scannow”
- It initiates scanning of your computer and displays errors
- Next, follow the on-screen instructions to fix errors
If you are still getting Outlook error 421 even after following above-mentioned steps, then try to reinstall your Windows and Outlook. If it doesn’t help you to resolve the issue, then use Outlook Repair tool and fix PST file as this error sometimes occurs due to PST corruption. You can also use this Outlook Repair tool to fix Outlook error 0x800ccc05. After completion of repair process, run your Outlook to check if still error appears or not.