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Flash Tester Notes on Flash Cookies

NOTE: Other than removing broken links, this page has not been updated or reviewed since Nov. 2014.

Flash Cookies - An Introduction

    (a.k.a. Flash Local Shared Objects, LSOs, super cookies, zombie cookies, and PIE (persistent identification element)

  • Eliminate Flash-spawned 'zombie' cookies by Woody Leonhard August 2010 (alternate link)
  • Local Shared Object article at Wikipedia
  • What are Local Shared Objects from Adobe
  • You Deleted Your Cookies? Think Again Wired August 2009
  • Cookies, Flash Cookies, Paywalls, and Tracking by Jerry Pournelle (second story, scroll down) August 2010. Also, short follow-up here
  • Flash Cookies - The Silent Privacy Killer October 2008

Flash Cookies - Defending Against

  • How to disable third-party local shared objects from Adobe. Seems like a great idea to me
  • How to manage and disable Local Shared Objects from Adobe - has multiple broken links
  • The Global Storage Settings panel from Adobe is where you can disable Flash cookies. You can either disable all Flash cookies (set the storage slider to zero) or simply disable third party Flash cookies (using checkbox). Some people have claimed this doesn't always work, I haven't tested it.
    The Chrome browser will take you here too. In version 6: click on the wrench, then Options, then the Under the Hood tab, then the Content Settings button, then click on Cookies in the left side column, and finally then click on "Adobe Flash Player storage settings..." at the bottom of the window. Whew.
  • Website Storage Settings Manager from Adobe. The official way to delete Flash cookies. Lets you see which websites have placed Flash cookies on your computer and how much storage they are using. You can delete all Flash cookies or just some.
  • See Adobe's documentation on their online web pages for managing Flash. Warning: boring.
  • The very popular CCleaner from Piriform can remove Flash cookies under Windows 7, Vista and XP, both 32-bit and 64-bit editions. Flash is in the Applications tab, look for the Multimedia section. There is also a portable version of CCleaner. See also Completely remove flash cookies with CCleaner for tips on using CCleaner to remove Flash cookies. It looks like good advice but I don't know the author and haven't yet tested it.
  • FlashCookiesView from Nir Sofer at nirsoft.net. Mr. Sofer is an excellent programmer who makes a ton of very useful, free, portable applications. This, however, is not one of his better programs. His website, however, is a treasure trove of great stuff.
  • KFC (Kill Flash Cookies) from Uri Fridman is free and runs under Windows, Linux and Macs. I haven't tried it.
  • Objection is a Firefox extension that doesn't seem to be ready yet
  • Flash Cookie Cleaner for Windows. I have not tried it and don't know anything about the company behind it. See CNET review.
  • MAXA Cookie Manager supports Windows 98/Me/XP/2000/Vista/2008 and Windows 7 (both 32 bit and 64 bit Windows versions). I haven't tried it.
  • Here's a suggestion I read on the Internet from a total stranger. Sounds reasonable. Find in your OS where Flash cookies are stored (see topic below). Rename or delete the folder (with all other software shut down). Then, you can prevent the folder from being re-created by creating a FILE with the folder name. This works because Windows doesn't allow a folder and a file in the same directory with the same name. I haven't tried it - it may well break some websites.
  • Flash Cookies and How to Get Rid of Them from the Mischel Internet Security blog. January 2010. About deleting the bread crumbs that Adobe leaves behind when it deletes Flash cookies.

Macs and Flash Cookies

Removing Flash cookies on a Mac

  • KFC (Kill Flash Cookies) from Uri Fridman is free and runs under Windows, Linux and Macs. I haven't tried it.
  • Flush.app Flash Cookie Removal Tool For OS X
  • MacCleanse 2 claims to erase caches, logs, cookies, histories, and more. I have not used it.

I'm not a Mac user, anyone who wants to fill me in on the Flash environment for Macs, feel free to email me at my full name (below right) at gmail.


KFC (Kill Flash Cookies) from Uri Fridman is free and runs under Windows, Linux and Macs. I haven't tried it.

Cookies - What's Next

Flash cookies were the second generation of cookies, now we are starting to see the third generation, implemented with HTML5.

  • Advertisers get hands stuck inside HTML5 database cookie jar About the RLDGUID Safari database from Ringleader Digital found on iOS based devices. September 2010.
  • Lawsuit Targets Mobile Advertiser Over Sneaky HTML5 Pseudo-Cookies from Wired. September 2010.
  • How to store website data with HTML5 from PC Pro magazine. September 2010.
  • Techie details on Structured client-side storage in HTML5

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October 9, 2017 9 PM CT
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