Chrome version 6.0.472.55 was an incremental update to a new version of Chrome released on September 7 and announced here. There was a bug in the JavaScript engine that reported the wrong type of some JavaScript objects in a very specific case. This caused Chrome to incorrectly execute Google Analytics' JavaScript, providing an artificially high visitor count for some websites, for their visitors using that particular version of the Chrome browser. Note, not all Google Analytics accounts were affected. The affected period will vary for accounts but would not have appeared before September 7.
A fix was released for all versions of Google Chrome on Wednesday, September 22. Chrome users were automatically updated to version 6.0.472.63 over the last few days.
You can determine whether a profile was affected by comparing visit data from September 7 to approximately September 22 with a previous date range. If you think your account was affected and want to segment out visits from that date range from the affected Chrome release, you can create an advanced segment similar to this one.
We are working closely with the Chrome team to ensure that an issue like this does not happen again. While we believe this issue is fixed, we’ll be closely monitoring this issue over the weekend and beyond.
