An ultimate guide to resolving the “Avast won’t Update virus definitions” error.

Securing the system from any possible threat is the priority of everyone. Having a robust security software installed in your system is of prime importance because of an ever-evolving set of security threats. But what if your screen displays “Avast won’t update virus definitions” or “avast virus definitions won’t update” message, thereby setting your system open to every possible menace.

Before getting into the solutions for the above error, let’s get a brief idea about the Avast Antivirus software.

Security software is a general term used to describe any software that shields your system from malware, virus, and spyware. Today we have a copious amount of security software, both paid and free, available for detecting, fixing, and preventing security vulnerabilities. We all must have heard or used various security software to date, but one name that’s common in this business is the Avast Antivirus. You can check out all the details of the avast cleanup premium review, which ultimately helps you in selecting one of their premium plans.

avast won't update virus definitions

Computer security, Browser security, antivirus software, anti-phishing, anti-spam, and much more similar applications form the Avast Antivirus menage. This is cross-platform security software that has been the most popular vendor on the market, with the largest share of the market for antivirus applications as reported in March 2012. Since then, Avast is one of the most popular antivirus software among many across the globe.

According to the recent stats as of April 2020, Avast holds nearly 12% of the shares of the anti-malware applications market. The software is hence standing strong with the second position in the entire market, with just Semantic Corporation ahead of it.

April 2020 stats

  Well, The numbers say it all about its popularity across the world.

The software is available in as many as  45 languages, which is also one important factor for its popularity among people across the globe.

But why is this software dominating the market despite having plenty of competitors?

Let’s find the answer to this question by going through the following points on the free version of Avast Antivirus:

  • The software is too good to be available for free. It offers some great features and applications which are available in the paid versions of its competitors( or even not available in either version of much similar software.)
  • Protects your system from dangerous URLs.
  • Great results for independent testing/hands-on tests
  • Network security inspector.
  • Password Manager-Allows you to manage your Password

The software got great reviews for its recently updated version. Here’s the recent rating by Neil J. Rubenking, a Lead Analyst for security.

Rating: 4.0

It could be a bit annoying when a window pops displaying- “Avast won’t update virus definitions ” 

So what does this message convey?

This message informs the users that virus definitions have not been updated, which might result in your system being subject to numerous online threats like viruses and malware.

Nearly every user of Avast Antivirus software must have encountered such pop up while using it. 

You must be figuring out reasons for avast not updating virus definitions. Here are few reasons for avast not updating virus definitions message listed below:

  • Incompatibility issues– The Avast virus update is not compatible with the Windows version you’re working on.
  • Installation- The installation of this software may not be done correctly and as a result you are getting avast not updating virus definitions error.

Now that we know the probable reasons behind this error, let’s check out some ways with which we can relinquish these pop-ups and continue working on a well-protected and secured system.

1. Update And Repair.

Windows must be regularly updated to maintain the compatibility of your OS with the Avast Antivirus software. Therefore scrutinize your system for any pending updates and install them.

Reduce the CPU load by updating the Avast software. To perform the updation stick to the following steps:

  • Go to the Windows Notification center. Open Avast Settings Management Dashboard.
Avast settings management dashboard
avast won’t update virus definitions
  • Check the current versions and virus definitions of the antivirus program under the Update Tab
  • Check for any pending updates and click Update.

There you go! The avast virus definitions won’t update issue is resolved.

However, in case of no pending updates you need to repair your Avast installation files. 

  • Open Control Panel<Programs<Program and Features<Avast Antivirus.
Control panel
Click on Programs
Program and features menu
Click on Programs and Features
Programs menu
Type Avast Antivirus in the search bar at the top right corner.
  • Click Repair after selecting the program.
  • Wait till the changes are made to the data files. Avast will hence repair the client software.
avast won’t update

NOTE– Restart the PC to check whether or not the error is removed.

The avast won’t update virus definitions issue will finally be resolved once the system is restarted.

2. Reinstall Avast

In case the avast not updating virus definitions problem isn’t resolved by the above method, you need to reinstall the Avast Client Software. For this, you’ll require a power uninstaller.

 Also, you can do a clean Uninstall by booting into safe mode and then doing the uninstallation.


  • Open the Run dialogue by typing Run in the search box or click Win+R and then type msconfig. Press Enter.
  • Click the Safe Boot in the Boot Tab as shown below.
Boot menu
Check the box next to Safe Boot
  • Check the box next to Safe Boot. Press Apply followed by OK.
  • Boot into Safe mode automatically by restarting your PC.
  • Once in safe mode, Run avastclear.exe that you did download earlier on your PC. This clears all the residual files.
  • Boot in normal mode. Download and install the latest version of Avast from the official website.
Avast official website
avast won’t update
  • This would remove the “Avast won’t update virus definitions” errors by removing the corrupted files.

 You can even do the clean installation by following a rather simple path:

  • Go to control panel<Programs<Programs and Features.
  • Select Avast Antivirus from the list by typing the name in the search bar at the top right corner of your control panel window.
  • Select the software and click uninstall. Once the uninstallation is complete, the corrupted files are removed and your system is ready for a clean installation.
  • Reinstall Avast from the official website.

After reinstallation, you don’t get avast not updating virus definitions error. The problem gets resolved!

3. Customer Support

When even the reinstallation method fails to solve the issue and your avast not updating virus definitions still, then there’s surely a deeply ingrained problem. 

Well, in that case contacting Avast Customer care is the ultimate solution.

4. In-built Troubleshooting


It’s often quoted that nothing could be better than self-repair. The same holds for the Avast Antivirus Software as well. 

This software has an IN-BUILT TROUBLESHOOTER which can resolve the “Avast won’t update virus definitions”. It can also solve various other potential compatibility and functionality issues. The process could be a bit tricky because it involves a few more steps as compared to the ones discussed previously in this article, but resolves the problem in one shot.

So, these are few ways using which you can resolve and avoid the updation errors associated with the much talked about antivirus software in the market.

An ultimate guide to resolving the “Avast won’t Update virus definitions” error. 1
Shivangi Kaushik
She's a final year electronics and communication engineering student from Uttar Pradesh. A gregarious and outgoing personality since childhood , who enjoys interacting with people and is always open to a healthy discussion on any topic. She's affable and confident enough to share her perspective and is a keen listener. Being an ex ICSE student, communicating and writing came naturally to her, which helped her write for various technical and non technical pages on the social media platforms and websites. . She has been actively volunteering and participating in various zonal and state level technical and literary events. Music is the ultimate soothing factor in her life and she likes to paint and sketch in her free time. She sights an exciting and stable career in the fields of Marketing and Public Relations in future.

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