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From time to time, when I browse the internet , after entering a site's URL , I get a warning message that a pop up has been blocked , then a question mark and a set of numbers appends itself after the URL.

It doesn't matter what site I want to navigate to, it can be a site I have developed, a well know site like for instance. Here's what happens:

    enter url:
    warning: pop up blocked
    url change to:

After checking the pop up ( which of course turns out to be an unwanted ad ), I deducted that the request and the pop up were linked.

This has never happened to me before, I'm not sure how this got started, how can I get rid of this? Clearing the cache , cookies etc... doesn't solve the issue.

I'm using a Macbook Pro OS10.6.7 , Chrome 13.0.782.24 beta.

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I am going to guess your computer is infected with Mac Defender or some variation of it. Have you tried using the release version of Chrome? – Ramhound Jun 21 '11 at 16:16
Just installed the release version, seems clean so far...thx – PatrickS Jun 22 '11 at 3:27

Your computer is probably infected with SpyWare. Apple provides a tool that you can use to scan for, and remove, malicious software such as SpyWare, and I'm hoping it can detect and remove whatever has infected your system:


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I have removed two tracking cookies with Macscan. Thx! nothing else though... – PatrickS Jun 22 '11 at 9:12
I'm hoping someone else will suggest some alternatives to MacScan that can detect and remove other SpyWare, including whatever is on your system. – Randolf Richardson Jun 23 '11 at 3:33
Most Tracking Cookies are typically benign as far as running code on your computer is concerned, but they do represent a possible privacy invasion. For example, with many advertising networks a cookie is set when the ad is first displayed, and then with the same ad network on different sites the network can effectively track your movements among the sites that their ads appear on. I don't approve of this practice (unless the user gets to choose AND the tracking is disabled by default), but unfortunately this problem is very subtle so most users don't even know that it's happening to them. – Randolf Richardson Jun 23 '11 at 3:36
Using Macscan hasn't actually cleared the problem, as you say these tracking cookies seem to have been quite benign. I had two systems with the same problem, one of the system was already with Chrome's release version. I have reinstalled Chrome on both systems, it looks like the problem has been cleared for now... Thanks! – PatrickS Jun 23 '11 at 5:17
Thanks for indicating that re-installing Chrome was the solution to your problem (+1). – Randolf Richardson Jun 23 '11 at 6:22

Thanks for your answers. I can't say I found the exact reason for this pop up behaviour but simply reinstalling Chrome seems to have cleared the problem ( at least for now ). I wanted to wait a couple of days in order to make sure and so far, there hasn't been any repeat.

The problem has reappeared and I'm pretty confident that my computer is not infected. I have purchased a new Macbook Pro & installed Intego's software, entirely scanned the computer and the problem only appears when I'm not on a VPN..

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