Google cited capacity as the reason for putting the brake on downloads of the software, which is designed to speed the delivery of Web pages. A message on the site said the company has reached its "maximum capacity of users and (we) are actively working to increase the number of users we can support".
The software was launched on 4 May but within a day was causing concern among users when it transpired that the software cached more data than many people felt comfortable with, enabling individuals in some cases to log into secure online pages of others.
Google Web Accelerator, which was released in beta, is set up to automatically work with Firefox and Internet Explorer once it has been downloaded. The service stores copies of sites frequently accessed by individual PCs and automatically retrieves new data from those pages, so that a Web browser needs to process only updates to those sites when asked to load them. It can also automatically "pre-fetch" frequently used Web sites before the user downloads it.
On a Google Labs discussion group, one user said that the security implications of Google caching details of Internet sessions were unacceptable. In a statement at the time, Google said the service can receive information such as the user's IP address, computer and connection information, and "personally identifiable information", such as an e-mail address. But, it said, information entered in SSL connections, such as Internet banking, will not be cached.
A Google spokesman on Wednesday morning denied that the removal of the tool was connected to the security fears. "It is a limited beta," he said, "and we reached the capacity of users."
ZDNet UK's Matt Loney reported from London. For more coverage from ZDNet UK, click here.