Flash cookies, or Local Shared Objects, are used for a variety of purposes: from Flash game saves to storing site preferences or user tracking.
If you do not play browser games, at least none that are Flash-based, and also do not visit websites or services regularly that make use of Flash to save site preferences or other content, you may want to consider disabling Flash cookies permanently in the browser. And even if you visit sites regularly that save content, you may still want to consider disabling third-party Flash content that sites may store on your device.
Note that it may have unforeseen consequences but that is usually resolved quickly. All you need to do is enable the feature again to make use of it in the browser of choice.
Update: Only some browsers support Adobe Flash in 2018. The technology is on its way out; Adobe announced that it plans to retire Flash in 2020. Most browsers set Flash to click-to-play which means that Flash won't be activated unless you interact with the content or have whitelisted the site previously. End
There are two primary options to prevent the saving of third-party Flash cookies on the system. You can either disable Flash which may not always be what you want as it will prevent all Flash content from being loaded in the browser, or make changes to the Flash configuration.
Visit the following website in a web browser that supports Flash. The global storage settings panel specifies the amount of disk space websites can use to store information on the computer.
Some websites may not only save first-party data on your system, but may also load content from other sites, an advertising banner, a Facebook like button or other scripts, that are then allowed to save data on your system as well.
Advertising companies use this system to save cookies on user systems to track them across domains. The company does not need to own the domains for that, all that is required is that the webmaster embeds scripts on the website that access third-party domains for that to happen.
You can uncheck the "allow third-party Flash content to store data on your computer" preference to prevent this from happening to your system in the future. The main site you are on can still save contents while all third party scripts can't anymore. Note that sub-domains are seen as third party sites.
If you are certain that no site you visit uses Flash cookies to save important information, you can set the global storage slider to None to do so. Most sites should work just fine after you have done so. As noted earlier, some sites may not function properly if the allow third party content option is unchecked.
If you prefer to keep everything as is to avoid any issues with sites you visit regularly, you may be interested in programs that help you clean Flash cookies from your system regularly.
Last but not least, it is possible to change the settings for a specific application. To do so right-click on the Flash application to open the settings menu for that app.
You can modify the storage that you want the application to use. If you want to block it, simply set it to none.
Ghacks is a technology news blog that was founded in 2005 by Martin Brinkmann. It has since then become one of the most popular tech news sites on the Internet with five authors and regular contributions from freelance writers.