Some third-party add-ons (Extensions and/or Plugins) use the Windows (IE) default location. Other third-party add-ons use their own history/cache locations. You can not really stop it, just keep it cleaned up. (Settings > Control Panel > Internet Options >Browsing History > Delete) To see the Firefox cache locations/contents, type '''about:cache''' in the URL/location bar just like typing a website address. See: http://kb.mozillazine.org/About_protocol_links Your Firefox history (and bookmarks) are stored in your profile folder in a database, places.sqlite. -------------------------- <br /> The information submitted with your question indicates that you have out of date plugins with known security and stability issues that should be updated. To see the plugins submitted with your question, click "More system details..." to the right of your original question post. *Adobe PDF Plug-In For Firefox and Netscape "9.3.4" *Next Generation Java Plug-in 1.6.0_21 for Mozilla browsers #'''Check your plugin versions''': http://www.mozilla.com/en-US/plugincheck/ #*'''Note: plugin check page does not have information on all plugin versions''' #'''Update Adobe Reader (PDF plugin):''' #*From within your existing Adobe Reader ('''<u>if you have it already installed</u>'''): #**Open the Adobe Reader program from your Programs list #**Click Help > Check for Updates #**Follow the prompts for updating #**If this method works for you, skip the "Download complete installer" section below and proceed to "After the installation" below #*Download complete installer ('''if you do <u>NOT</u> have Adobe Reader installed'''): #**Use the links below to avoid getting the troublesome "getplus" Adobe Download Manager and other "extras" you may not want #**Use Firefox to download and SAVE the installer to your hard drive from the appropriate link below #**Click "Save to File"; save to your Desktop (so you can find it) #**After download completes, close Firefox #**Click the installer you just downloaded and allow the install to continue #***Note: Vista and Win7 users may need to right-click the installer and choose "Run as Administrator" #**'''<u>Windows only Download link</u>''': ftp://ftp.adobe.com/pub/adobe/reader/ #***Choose your OS #***Choose the latest #.x version (example 9.x, for version 9) #***Choose the highest number version listed #***Choose your language #***Download the file #***Windows: choose the .exe version #****NOTE: '''At this moment''', using this method, only the incremental update is available on the Adobe FTP server; download the .msp file under the "misc" folder, save it to your hard drive, exit Firefox, run the installer file and Windows Installer will install it for you. #**'''<u>OSX, Linux and Solaris Download link</u>''': http://get.adobe.com/reader/otherversions/ #*Also see: https://support.mozilla.com/en-US/kb/Using+the+Adobe+Reader+plugin+with+Firefox (do not use the link on this page for downloading; you may get the troublesome "getplus" Adobe Download Manager (Adobe DLM) and other "extras") #*After the installation, start Firefox and check your version again. #Update the [[Java]] plugin to the latest version. #*Download site: http://java.sun.com/javase/downloads/index.jsp (Java Platform: Download JRE) #*Also see "Manual Update" in this article: http://support.mozilla.com/en-US/kb/Using+the+Java+plugin+with+Firefox#Updates

Disable all plugins (Tools > Add-ons > Plugins) if you do not want those plugins to store information elsewhere. [[Private Browsing]] only makes Firefox not store data. Extensions and plugins (Flash 10.1 does) that do not recognize and support PB mode can still store data on disk. If you visit websites that use MS products like WMP or Silverlight then those plugins store their data in the IE temp cache or possibly the registry as well.