Do not delete the '6261' folder. Please delete the '6253' folder manually. The update happened from '6253' to '6261'. If you've already deleted the '6261' folder, uninstall SiteAdvisor from Add/Remove programs. Since you've a McAfee suite installed on your system, this would be present under McAfee Security Center. Select SiteAdvisor (only) from the programs listed and restart the system. Download the latest version of SiteAdvisor. Download link After installation, you could either wait for a day before the automatic updates to happen (or) unzip the chrome.manifest file attached and place the same in the appropriate location.