Avast antivirus software has a few different options you can use to scan your computer for malicious malware and hook it out before it has any chance to affect your PC.
These range from faster “quick scans” that will skim over recently downloaded and edited files and give you a fast result, which is usually run automatically on a set schedule. There’s also the “full virus scan” which does a deep scan of your entire computer.
The full virus scan is a much more robust method, and as such, it takes much longer to complete. However, some users run into the problem of the scan getting stuck permanently, and it will never complete until you manually cancel it.
In this article, we will discuss the potential causes of this issue, as well as some easy troubleshooting steps you can take to fix this and get your Avast antivirus working again.
Why is Avast’s full virus scan stuck?
There are a number of things that might cause your antivirus to get stuck, but first, we have to discuss the difference between being truly “stuck” and just exceptionally slow.
Many users have reported that their full virus scan has taken over 24 hours to fully complete, so anyone who is expecting it to finish in under an hour is going to have the impression that it’s completely dead.
However, just because it will eventually complete still doesn’t mean everything’s fine, and there are some steps we can take to try and speed this up.
First, we’ll go through the potential causes of this issue so you can get an idea of what might be causing the problem for you. Then, we’ll explain how to get everything fixed up.
Unlike a quick scan (or a “smart scan”), a full system scan has to go deep into the registry of your operating system and check all those zipped files, archives, and backups to root out any unsavory files that shouldn’t be there.
This process takes a much heavier toll on your system’s resources, particularly RAM and hard drive speeds.
If your computer doesn’t have the resources available to allocate to the virus scanning process, the software itself will often limit the amount of RAM, CPU, and hard disk processing it will allocate to this scan to allow you to continue using the computer as normal while the scan runs.
If your computer is really old, then perhaps you can’t even do that. In that case, we have to take a few steps to clear up some resources to make the software run a little faster.
When you install Avast Antivirus software, it comes with the Avast self-defense module. This is an extra piece of software that Avast very slyly installs and enables by default.
The intention of the module is to protect the Avast software from a possible attack from malware.
Malware and virus programmers understand that antivirus software will detect and delete their program before they have a chance to really do anything with it, so instead of trying to hide from the software, they actually aim to disable the antivirus software first so they can go about their nasty business unhindered.
Of course, as a user, this is not something we want, so if any attempt is made to uninstall Avast without our knowledge, we get a pop-up letting us know that some malicious software is trying to uninstall the program.
However, this self-defense module has been known to hinder the full virus scan process, and some users have reported that after disabling Avast self-defense, their scan has gone ahead and completed without issue.
“But if I disable the module, is my antivirus software vulnerable to attack?”
Windows also has its own notification system that will ask for your permission before uninstalling a piece of software, so even with this module disabled, you should still get an adequate heads up before your Avast software vanishes from the computer.
In fact, it’s even been recommended by the Avast support staff on their official forum for people facing this very issue.
File access conflicts
In order for Avast to fully scan a file, it needs access to have access to it. Usually, this doesn’t cause too much of an issue. However, some users have reported their Avast software getting stuck on seemingly random files.
This may indicate a permission or file access error. Normally, you don’t need to go in and address this on a file by file basis. It’s usually an indication that there is an issue with the installation that can be rectified by other means.
If, for example, the file causing the issue is a single .jpg on your desktop, you could always consider moving it from the drive you are scanning temporarily to let Avast finish and then move it back. But this is a troublesome method and should only be done if you are strapped for time.
Because anti-virus software gets updated so often, it’s pretty common to see installation issues related to corrupt files or problematic registry entries.
Even if your software was working fine one minute and then suddenly has a problem the next, a clean reinstall of the software will, in many cases, help to rectify this issue.
Avast also has its own repair feature built-in, which can help to scan the software for anything within the installation that needs correcting, which Avast support often recommends using.
It’s quite important that antivirus programs stay up to date to ensure they can deal with the current viruses and malware that are making the rounds. However, that’s not the only reason to keep software up to date. They also help to work out bugs and glitches that may be causing your scanning process to get stuck.
Similarly, your operating system needs to be kept up to date to ensure any compatibility issues are dealt with so the software can run as smoothly as possible.
Many people like to use external hard drives or NAS systems to store their data. This type of external storage solution has been known to cause access conflicts with antivirus software.
Unplugging these temporarily while you run the scan may help to either move it along faster or unstick it completely.
How to unstuck Avast full virus scan
There are numerous things that can potentially cause your antivirus to become stuck during its scan. Fortunately, all the steps we need to take to fix this are pretty simple and can be done by yourself without any prior technical knowledge.
Let’s go through some easy solutions to get your antivirus software back to working order.
Free up system resources
In many scenarios, your antivirus full scan is not actually fully stuck or frozen. It’s simply taking an unusually long amount of time (for some users, this has been well over 24 hours).
To help the software along and let it finish faster, we can try to free up some system resources by turning off any software or programs that aren’t needed right away, especially things like Google Chrome, which is well known for being a RAM hog.
In addition to that, if your computer is very old, it might be worth upgrading a few components, such as adding more RAM or getting a new CPU or faster hard disk to help the software perform better.
Of course, don’t run out and buy new computer components until you are completely sure this is the issue. Read on for more solutions.
Disable Avast self-defense
By default, a new installation of Avast antivirus will automatically both install and enable the self-defense module to help protect the software from any malicious attacks.
Although it’s not completely clear why, this module is known to cause the full scan to freeze, and users have reported that by disabling it, their software was able to fully complete the scan.
- Inside the Avast software, click the “settings” icon near the top right of the user interface.
- Next, navigate to the bottom tab called “troubleshooting.”
- There will be an option called “Enable Avast self-defense module”; uncheck this box.
- A warning pop-up will appear; click “yes” to continue.
Once this is disabled, restart your computer and run the scan again.
Update Windows and Avast
Sometimes the scan will hang due to there being a file the software is not able to access. While you certainly can go there and manually ensure the file is unlocked for Avast to access it, if there are a lot of files causing this, it can be very time consuming to deal with.
Before taking more drastic measures, ensure both your Windows OS and the Avast software itself are completely up to date, as this can often solve any communication conflicts between them and allow the scan to be fully complete without issue.
In some cases, even after everything is up to date, the issue can persist, which may indicate a corrupt installation file or a registry error that requires you to completely uninstall and reinstall the software.
You can use an uninstaller such as IObit Uninstaller, which will automatically detect and clean up any residual registry files after the uninstallation.
Once the software has been completely removed, you can reinstall it as normal.
Unplug any external devices
When it comes to accessibility issues, external data connected via USB is very prone to rejecting access to antivirus software. Therefore, if Avast is trying to scan an external device it doesn’t have access to, it may cause the scan to permanently freeze.
In this scenario, the best course of action is to unplug any external devices and see if the scan can complete without them plugged in.
Contact Avast support
If you have tried all the above-mentioned methods, it might be a more technical issue, in which case you may need to submit a support request on the official Avast forum. From there, a qualified support worker will help you to figure out why the software isn’t working on your PC.