Fast & free online virus scanner
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Frequently Asked Questions

  • Q1: What is Bitdefender QuickScan?
    A1: Bitdefender QuickScan is an online tool which uses "in-the-cloud" scanning to detect malware running on a PC very fast, usually in less than 60 seconds.
  • Q2: Why use Bitdefender Quickscan?
    A2: Because it's fast! Whenever you need a quick check or a second opinion, such as before logging in to your favourite game, when using your bank account online or buying something online, QuickScan is the best choice.
  • Q3: How to perform a QuickScan?
    A3: To launch a QuickScan you just need to visit and click 'Scan now'. For even faster access, Bitdefender QuickScan is also available as Firefox and Chrome extensions.
  • Q4: How is QuickScan different from other online scanners?
    A4: In a single word: speed. Most online scanners are merely legacy on-demand scanners that are downloaded (along with a huge virus database) and then used to scan your PC as you would do with a normal Antivirus program. This can usually take from 30 minutes to one hour.
    Bitdefender QuickScan takes full advantage of the "in-the-cloud" scanning technology and is capable to detect active malware in less than a minute, taking just a fraction of the system resources needed by a regular virus scan. Moreover, there is no need for annoying virus signature updates, as the entire virus database and the scanning engines are hosted on remote servers.
  • Q5: How can QuickScan be so quick?
    A5: In a nutshell, QuickScan makes a list of digital fingerprints (or hashes) of the programs that are running and of other critical files. It then sends this list to the server. If the server doesn't recognize a hash, it requests the file to be uploaded so it can be thoroughly analyzed. When the analysis is complete, the server returns a 'clean' or 'infected' verdict for every file in the list.

    The first time you run QuickScan on your system it may find a lot of 'unknown' files, so it's normal for the scan to take longer. After using QuickScan a few times you will notice that it becomes faster and faster. This is because once the server receives and scans a new file, it will subsequently recognize it by its hash and never request it again.
  • Q6: The report shows Quickscan skipping many files. Why is that?
    A6: To optimize the hashing and communication process several types of files which were deemed harmless are skipped.
  • Q7: QuickScan didn't detect the infected files that other antivirus solutions found! What's going on?
    A7: QuickScan only detects viruses which are active in memory or present in files that are run at system startup. Inactive virus bodies are not scanned for and therefore not detected. To run a full system scan you can use Bitdefender Online Scanner or one of the Bitdefender security solutions.
  • Q8: Will QuickScan delete files, ship credit card data to unknown parts or otherwise cause harm?
    A8: No. Quickscan does not modify or delete any file on your system and only uploads executable files for checking (i.e. NO documents or other data files are sent). The upside to that is you're safe. The downside is that Quickscan provides no virus removal either.
  • Q9: What if Quickscan says my system is infected?
    A9: To keep Quickscan as fast as possible, we didn't include any cleaning capabilities. Please run a full system scan using Bitdefender Online Scanner or one of our commercial offerings.
  • Q10: What browsers are supported?
    A10: Microsoft Internet Explorer, Mozilla Firefox.
  • Q11: Is there any direct link to the developers and parties involved in the project?
    A11: The e-mail address „qscan at bitdefender dot com” was specifically created to provide a simple way to communicate development issues.
  • Q12: QuickScan crashed. Firefox/IE crashed. What happened?
    A12: It may happen (though very rarely) that a bug slipped through our QA process and made it in a QuickScan version. Best course of action is to make sure you have the very latest version installed.
    • In Firefox click Tools -> Addons and click the "Find Updates" button in the lower right section of the addon window.
    • The Internet Explorer component will be automatically updated once you access the QuickScan website).
    If the problem persists, you are encouraged to contact us at quickscan at bitdefender dot com and we'll promptly get back to you and try to figure out what's wrong.
  • Q13: How do I uninstall QuickScan from my Browser?
    A13: If you just dropped the npqscan.dll file in the plugins folder of your web browser, you need to simply remove the file and restart the browser.
    • For Firefox you should go to Tools -> Add-ons, select Bitdefender QuickScan and press the Uninstall button.
    • For Internet Explorer you can either use the Browser's facility for managing extensions or delete all the files starting with qsax from C:\WINDOWS\Downloaded Program Files.
    We would really love to hear about any improvements or troubles you had so don't forget to drop us an e-mail at „qscan at bitdefender dot com” and share with us your experience with this technology.
  • Q14: On Windows Vista or later with UAC enabled, the Internet Explorer runs in Protected Mode and QuickScan can't scan the memory.

    run as admin in vista To temporary disable the Protected Mode and allow memory scanning, please run Internet Explorer as Administrator.

    To start IE as administrator you need to select the application from your start menu (note: NOT the desktop icon), right click it and select "Run as Administrator".

    You can easily find it by typing "explorer" in the quick-search area after pressing the Start button.