CoolPreviews – You Ruined My Day!

OK, maybe “you ruined my day”, is an exaggeration, but…..

Let me start by saying I love CoolPreviews – a Picture-in-a-Picture free Browser add-on, that lets me preview links and rich media content, without clicking the link, or leaving my current page.

I use this tool every day to confirm that the links in my “Tech Thoughts Daily Net News” column are live. The screen capture below illustrates how this works.

CoolPreviews bug

I just cursored over the link, in this case ““CNET Free Security Starter Kit: Refined for 2010”, and CoolPreviews opened a preview window of the referenced link. Pretty cool, no?

But then there was yesterday. CoolPreviews, you definitely tried my patience.


Early in the morning on opening my primary Browser, Firefox, I was greeted by loud PacMan like music that I could not shut down. First thought – a malware infection. Drat – the first one in two years; maybe even longer.

Since mornings are a huge rush time for me, I simply closed Firefox and opened Chrome. Hmm, no PacMan music. So, probably not a system wide infection, but a possible Firefox infection.

After finishing what work I could using Chrome, I turned to the problem with Firefox. I won’t go through the whole process, but it went something like this:

Booted to Avira Rescue Disk – no infections found.

Ran on board Microsoft Security Essentials, Malwarebytes Free Edition (secondary scanner), and SuperAntiSpyWare Free Edition (secondary scanner). No joy.

Uninstalled Firefox using Revo Uninstaller, since it was important to remove all Registry entries.

Reinstalled Firefox and launched – hey, no PacMan music.

Ran MozBackup to restore my add-ons, bookmarks, mail, contacts, history, extensions, passwords, cache etc.

Relaunched Firefox – oh no, PacMan Music. But some headway – now I know that the likely cause is a compromised Firefox add-on.

Disabled all add-ons, and then re-enabled one at a time, until CoolPreviews  proved to be the guilty party.

Now, this whole exercise didn’t take all that long – the biggest time waster was in running deep scanning mode with my AVs. Diagnosing the problem after this part of the process, was a no-brainer.

Later in the day, CoolIris, the CoolPreview developer, finally posted on this problem. Here’s what  they had to say:

Google launched a homepage today which features an interactive PacMan game, with music, sirens, etc. If CoolPreviews is enabled, the music plays even if you don’t have Google opened in your browser tab. We apologize for this inconvenience.

But, that’s hardly what I call an explanation. The real cause of this  “bug” was pre-fetching. In this case, CoolPreviews pre-fetching the Google Home page. So, here’s a suggestion for CoolPreviews – STOP pre-fetching.

Pre-fetching might appear to be sexy but it is not universally admired. Some of the issues include, unwanted cookies, increased bandwidth usage, and  possible exploitation by unwanted sites.

In any event, this “bug” issue won’t dissuade me from using CoolPreviews. In the long run, it’s just too valuable in my day to day computing.

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Filed under Browser add-ons, Browsers, downloads, Free Anti-malware Software, Freeware, Interconnectivity, Manual Malware Removal, Software, Uninstall Tools, Windows Tips and Tools

18 responses to “CoolPreviews – You Ruined My Day!

  1. I knew Pac Man would get you sooner or later… He really caused you alot of work; BUT, you figured it in the end. I too, just yesterday, learned about (and actually) visited the Google search page with the Pac Man Game… The Prefetching feature of CoolIris, if continued, could ultimately fetch the wrong bone (major security issue in my opinion). Your article most likely served to help a ton of people who experienced the same thing you did.


    • Bill Mullins

      Hey Rick,

      Which is why PacWoman was always my favorite. lol

      Pre-fetching can definitely be dangerous. There aren’t too many sites that are fussy about it – it just eats up their bandwidth.

      Good to hear from you on a Saturday.


  2. Liam O' Moulain


    Great article, but I’m gonna stay away from this app – at least for now.


    • Bill Mullins

      Hey Liam,

      Overall, the developer’s response was appropriate, so don’t be too hard on these guys. lol


  3. John


    The latest update about pacman and the fix.


    • Bill Mullins

      Thanks John, I had seen that.

      Still, not a satisfactory answer when the real cause is/was prefetching (loading the Google page in the background). This is not the only page that is currently prefetched. This should be optional for those who would choose to turn this feature off.



  4. John


    OK, I have D/L this little app and so far so good, and as you say it does save you lots of time by not having to open other windows, which for me is a bonus.

    But you have kind of lost me with the pre fetching thing which I assume is not such a good thing?


    • Bill Mullins

      Hey John,

      Well, it’s a great app – couldn’t live without it really.

      I won’t reinvent the wheel and give you my definition of prefetching, instead, here’s something from Wikipediathat encapsulates my views.

      Link prefetching is a draft standards compliant mechanism used by some web browsers , which uses browser idle time to download or *prefetch* documents that the user might visit in the near future. A web page provides a set of prefetching hints to the browser, and after the browser is finished loading the page, and after an idle time has passed, it begins silently prefetching specified documents, storing them in its cache. When the user visits one of the prefetched documents, it can be served up quickly out of the browser’s cache.

      There are a number of criticisms regarding the privacy and resource usage implications of link prefetching:

      – Users and website operators who pay for the amount of bandwidth they use find themselves paying for traffic for pages the user might not actually visit, and advertisers might pay for viewed ads on sites that are never visited. – Web statistics such as browser usage, search engine referers, and page hits may become less reliable due to registering page hits that were never seen by the user. – Users may be exposed to more security risks – by downloading more pages, or from un-requested sites (additionally compounded as drive-by downloads become more advanced and diverse). – Web providers may find themselves at liability of third-party content outside of their domain that could be hot-swapped, however search engines have made it heavily accepted that one should have no liability of what one links to, and this is only slightly different through making it more mandatory that one gets the links content.

      Yes, it may have a positive impact on speed. But tell me, can you measure micro seconds? So, my question is, if we can’t actually humanly time the benefit, and we know there can be substantial downsides, why do we do it?

      Personally, I turn off prefetching in my Browsers. The developer’s of CoolPreviews should allow me to do the same thing.



  5. John


    Thanks for a very thorough explanation, it all makes sense now.


  6. Pingback: CoolPreviews – You Ruined My Day! « Bill Mullins' Weblog – Tech … | Firefox Blog

  7. Ranjan

    Hi Bill,
    Nicely and neatly explained article…
    Was just about to try, but the pre-fetching thingy changed my decision..
    I don’t like prefetching at all..
    Will wait until they add an option to turn it off..

    • Bill Mullins

      Hey Ranjan,

      You’re right – an option to turn off prefetching is a necessity. Like you, I’m not a fan of prefetching.


  8. RHH (robert)

    Hi Bill,

    Just wanted to say a big THANKS for posting the matter on Cool Iris, it helped me to follow your strategy procedure to address the problem at it’s onset. I will now download Mozbackup and Chrome to use to address suspected browser issues in the future.

    When it hit us yesterday, fortunately Google had already included forum remarks in Mozilla that people had posted fingering Cool Iris as the problem, and we immediately deleted it for the fix. Looking there first might be time saver in the future if similar Firefox problems arise.


    • Bill Mullins

      Hi Robert,

      No, Googling this issue was of no help to me. I had the problem solved 5 hours *before* CoolPreviews (or Google), even took note of the problem. An average user, as you suggest, would benefit from searching for solutions to problems like this.

      Mozbackup, for Firefox users, is an essential tool for recovery, and should be stored either on a separate partition, or a USB drive.


  9. rasberri8

    Is there something like this for IE8 XP? I don’t have Windows 7 though.

    • Bill Mullins

      Hey Rasberri8,

      Sorry, this app is not compatible with either IE 7 or 8 – Firefox only.

      BTW – you don’t need Win 7.


  10. thoraX

    Hi Bill, I like honest people like you & in security
    is not bulet_proof app. We use our *instinct or people call it common-sense* also important how to deal with disater to our machine 🙂
    Good job,Bill.

    • Bill Mullins

      Well thank you ThoraX.

      You’re right – Instinct/common sense is part of the key to remaining safe on the Internet.

      Good to hear from you.