Remove “Ads by PDFdefault” adware (Virus Removal Guide)

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Written by: Stelian Pilici

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PDFdefault is an adware program that displays pop-up ads and unwanted advertisements on web pages that you visit. These advertisements will be shown as boxes containing coupons, as underlined keywords (in-text ads), pop-up ads or advertising banners.

PDFdefault adware

What is PDFdefault?

PDFdefault is advertised as program that will improve your browsing experience while online. Though this may sound like a useful service, the PDFdefault program can be intrusive and will display advertisements whether you want them to or not.

The PDFdefault advertisements may have a different text under the pop-up: “Powered by PDFdefault“, “Brought to you by PDFdefault“, “RocketTab powered by PDFdefault“, “Ads by PDFdefault” or “Ads powered by PDFdefault“.

These ads are aimed to promote the installation of additional questionable content including web browser toolbars, optimization utilities and other products, all so the PDFdefault publisher can generate pay-per-click revenue.

Pop-up Ads from Adware

When your machine is infected with the PDFdefault adware, other common symptoms include:

  • Advertising banners are injected with the web pages that you are visiting.
  • Random web page text is turned into hyperlinks.
  • Browser popups appear which recommend fake updates or other software.
  • Other unwanted adware programs might get installed without the user’s knowledge.

To make matters worse, you will also find that PDFdefault will cause your computer to act more sluggish or for your web browser to freeze.

How did PDFdefault get on my computer?

PDFdefault is commonly bundled with other free programs that you download off of the Internet. Unfortunately, some free downloads do not adequately disclose that other software will also be installed and you may find that you have installed PDFdefault without your knowledge.

You should always pay attention when installing software because often, a software installer includes optional installs, such as this PDFdefault adware. Be very careful what you agree to install.
Always opt for the custom installation and deselect anything that is not familiar, especially optional software that you never wanted to download and install in the first place.
It goes without saying that you should not install software that you don’t trust.

How to remove PDFdefault adware (Uninstall Guide)

This page is a comprehensive guide which will remove PDFdefault adware and other malicious programs that may be installed on your machine.
Please perform all the steps in the correct order. If you have any questions or doubt at any point, STOP and ask for our assistance.

To remove PDFdefault Ads, follow these steps:
STEP 1: Uninstall PDFdefault 1.0 from Windows
STEP 2: Scan your computer with AdwCleaner
STEP 3: Scan your computer with Malwarebytes Anti-Malware
STEP 4: Double-check for malware with HitmanPro

STEP 1 : Uninstall PDFdefault 1.0 from Windows

In this first step, we will try to identify and remove any malicious program that might be installed on your computer.

  1. Go to the uninstall menu.

    Windows 10 or Windows 8

    1. To uninstall a program on Windows 10 or Windows 8, right-click on the Windows Start button and choose “Control Panel” from the pop-up menu.
      Control Panel in Windows 10
    2. When the “Control Panel” window opens click on the “Uninstall a program” option under “Programs” category.
      Uninstall A Program on Windows 10

    Windows 7 or Windows Vista

    1. If you are using Windows XP, Windows Vista or Windows 7, click the “Start” button, then click on the “Control Panel” menu option.
      [Image: Control Panel in Windows Start Menu]
    2. When the “Control Panel” window opens click on the “Uninstall a program” option under “Programs” category.
      [Image: Uninstall a program]
  2. When the “Programs and Features” screen is displayed, scroll through the list of currently installed programs and uninstall “PDFDEFAULT 1.0” .
    The malicious program may have a different name on your computer. To view the most recently installed programs, you can click on the “Installed On” column to sort your program by the installation date. Scroll through the list, and uninstall any unwanted or unknown programs.

    If you are having issues while trying to uninstall the PDFdefault program, you can use Revo Uninstaller to completely remove this unwanted program from your machine.

    Uninstall PDFdefault 1.0

    If you cannot find any unwanted or unknown programs on your machine, then you can proceed with the next step.

STEP 2: Scan your computer with AdwCleaner

AdwCleaner is a free utility, which will scan your computer and web browser for the “Ads by PDFdefault” adware.

  1. You can download AdwCleaner from the below link.
    ADWCLEANER DOWNLOAD LINK (This link will open a new web page from where you can download “AdwCleaner”)
  2. Before starting AdwCleaner, close your web browser, then double-click on the AdwCleaner icon.
    Start AdwCleaner
    Picture of User Account Control If Windows prompts you as to whether or not you wish to run AdwCleaner, please allow it to run.
  3. When the AdwCleaner program will open, click on the “Scan” button as shown below.
    AdwCleaner Scan button
    AdwCleaner will now start to search for the PDFdefault adware and other malicious files that may be installed on your computer.
  4. To remove the malicious files that were detected in the previous step, please click on the “Cleaning” button.
    Remove PDFdefault adware with AdwCleaner
  5. AdwCleaner will prompt you to save any open files or documents, as the program will need to reboot the computer to complete the cleaning process. Please do so, and then click on the “OK” button.
    AdwCleaner removing adware
    When your computer reboots and you are logged in, AdwCleaner will automatically open a log file that contains the files, registry keys, and programs that were removed from your computer.

STEP 3: Scan your computer with Malwarebytes Anti-Malware

Malwarebytes Anti-Malware is a powerful on-demand scanner which will remove the PDFdefault adware from your machine. It is important to note that Malwarebytes Anti-Malware will run alongside antivirus software without conflicts.

  1. You can download download Malwarebytes Anti-Malware from the below link.
    MALWAREBYTES ANTI-MALWARE DOWNLOAD LINK (This link will open a new web page from where you can download “Malwarebytes Anti-Malware Free”)
  2. Once downloaded, close all programs, then double-click on the icon on your desktop named “mbam-setup” to start the installation of Malwarebytes Anti-Malware.
    Start Malwarebytes Anti-Malware setup
    Picture of User Account Control You may be presented with a User Account Control dialog asking you if you want to run this file. If this happens, you should click “Yes” to continue with the installation.
  3. When the installation begins, you will see the Malwarebytes Anti-Malware Setup Wizard which will guide you through the installation process.
    Malwarebytes Anti-Malware Installer
    To install Malwarebytes Anti-Malware on your machine, keep following the prompts by clicking the “Next” button.
    Malwarebytes Anti-Malware final screen
  4. Once installed, Malwarebytes Anti-Malware will automatically start and you will see a message stating that you should update the program, and that a scan has never been run on your system. To start a system scan you can click on the “Scan Now” button.
    Malwarebytes Anti-Malware Scan Now
  5. Malwarebytes Anti-Malware will now start scanning your computer for the PDFdefault adware. When Malwarebytes Anti-Malware is scanning it will look like the image below.
    Malwarebytes Anti-Malware Scanning for Malware
  6. When the scan has completed, you will be presented with a screen showing the malware infections that Malwarebytes Anti-Malware has detected. To remove the malicious programs that Malwarebytes Anti-malware has found, click on the “Remove Selected” button.
    Remove the malware that Malwarebytes Anti-Malware has detected
    Please note that the infections found may be different than what is shown in the image.
  7. Malwarebytes Anti-Malware will now quarantine all the malicious files and registry keys that it has found. When removing the files, Malwarebytes Anti-Malware may require a reboot in order to remove some of them. If it displays a message stating that it needs to reboot your computer, please allow it to do so.
    Malwarebytes Anti-Malware asking to restart PC
    After your computer will restart, you should open Malwarebytes Anti-Malware and perform another “Threat Scan” scan to verify that there are no remaining threats

STEP 4: Double-check for malware with HitmanPro

HitmanPro finds and removes malware, adware, bots, and other threats that even the best antivirus suite can oftentimes miss. HitmanPro is designed to run alongside your antivirus suite, firewall, and other security tools.

  1. You can download HitmanPro from the below link:
    HITMANPRO DOWNLOAD LINK (This link will open a new web page from where you can download “HitmanPro”)
  2. Double-click on the file named “HitmanPro.exe” (for 32-bit versions of Windows) or “HitmanPro_x64.exe” (for 64-bit versions of Windows). When the program starts you will be presented with the start screen as shown below.
    HitmanPro Installer
    Click on the “Next” button, to install HitmanPro on your computer.
    itmanPro while installing on PC
  3. HitmanPro will now begin to scan your computer for the PDFdefault malware.
    HitmanPro scanning
  4. When it has finished it will display a list of all the malware that the program found as shown in the image below. Click on the “Next” button, to remove malware.
    HitmanPro detected malware
  5. Click on the “Activate free license” button to begin the free 30 days trial, and remove all the malicious files from your computer.
    Remove malware with HitmanPro

Your computer should now be free of the PDFdefault adware infection. You can now remove AdwCleaner from your machine, however we recommend that you keep HitmanPro and Malwarebytes Anti-Malware installed and perform regular computer scans.

If you are still experiencing problems while trying to remove PDFdefault pop-up ads from your machine, please do one of the following:

How to Stay Safe Online

Here are 10 basic security tips to help you avoid malware and protect your device:

  1. Use a good antivirus and keep it up-to-date.

    Shield Guide

    It's essential to use a good quality antivirus and keep it up-to-date to stay ahead of the latest cyber threats. We are huge fans of Malwarebytes Premium and use it on all of our devices, including Windows and Mac computers as well as our mobile devices. Malwarebytes sits beside your traditional antivirus, filling in any gaps in its defenses, and providing extra protection against sneakier security threats.

  2. Keep software and operating systems up-to-date.

    updates-guide

    Keep your operating system and apps up to date. Whenever an update is released for your device, download and install it right away. These updates often include security fixes, vulnerability patches, and other necessary maintenance.

  3. Be careful when installing programs and apps.

    install guide

    Pay close attention to installation screens and license agreements when installing software. Custom or advanced installation options will often disclose any third-party software that is also being installed. Take great care in every stage of the process and make sure you know what it is you're agreeing to before you click "Next."

  4. Install an ad blocker.

    Ad Blocker

    Use a browser-based content blocker, like AdGuard. Content blockers help stop malicious ads, Trojans, phishing, and other undesirable content that an antivirus product alone may not stop.

  5. Be careful what you download.

    Trojan Horse

    A top goal of cybercriminals is to trick you into downloading malware—programs or apps that carry malware or try to steal information. This malware can be disguised as an app: anything from a popular game to something that checks traffic or the weather.

  6. Be alert for people trying to trick you.

    warning sign

    Whether it's your email, phone, messenger, or other applications, always be alert and on guard for someone trying to trick you into clicking on links or replying to messages. Remember that it's easy to spoof phone numbers, so a familiar name or number doesn't make messages more trustworthy.

  7. Back up your data.

    backup sign

    Back up your data frequently and check that your backup data can be restored. You can do this manually on an external HDD/USB stick, or automatically using backup software. This is also the best way to counter ransomware. Never connect the backup drive to a computer if you suspect that the computer is infected with malware.

  8. Choose strong passwords.

    lock sign

    Use strong and unique passwords for each of your accounts. Avoid using personal information or easily guessable words in your passwords. Enable two-factor authentication (2FA) on your accounts whenever possible.

  9. Be careful where you click.

    cursor sign

    Be cautious when clicking on links or downloading attachments from unknown sources. These could potentially contain malware or phishing scams.

  10. Don't use pirated software.

    Shady Guide

    Avoid using Peer-to-Peer (P2P) file-sharing programs, keygens, cracks, and other pirated software that can often compromise your data, privacy, or both.

To avoid potential dangers on the internet, it's important to follow these 10 basic safety rules. By doing so, you can protect yourself from many of the unpleasant surprises that can arise when using the web.

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