Add-ons and some websites require that you use a specific browser, and cause the following problems: * Websites report that your browser is incompatible, or suggest that you upgrade your browser. * You are not able to install extensions or themes from [http://addons.mozilla.org Addons.Mozilla.org] because you see one of the following messages, even though your version of Firefox is listed as compatible. ** ''This add-on is for older versions of Firefox'' ** ''Upgrade Firefox to use this add-on'' ;:{note}'''Note: Some websites or add-ons may be legitimately incompatible with your version of Firefox.'''{/note} If you have already verified that the website or add-on is compatible with your version of Firefox, the cause of the problem may be in your Firefox "User Agent" string, that identifies your browser type to websites. Common causes of this problem are installing Megaupload Toolbar extension or Creative ZENCast plugin and then updating Firefox. This article describes how to reset your user agent to remedy these problems. = Reset your user agent = To reset your user agent: # [[T:aboutconfig]]{for win}<br/> <br/> [[Image:badua-en-win-1.jpg]] <br/> <br/>{/for} # Search for '''useragent''' by typing it into the '''Filter''' field. # [[T:contextmenu]] on each of the three preferences listed below and select {menu Reset} from the context menu. ** {pref general.useragent.extra.firefox} ** {pref general.useragent.locale} ** {pref general.useragent.security} # If they exist, you may also need to reset: ** {pref general.useragent.extra.''productName''} - where ''productName'' can be the name of some third party software (e.g. ''microsoftdotnet''). ** {pref general.useragent.override} [[Image:reset_ua1.png]] After resetting your user agent, you may need to clear you cookies and cache: [[T:clearCookiesCache]] = If resetting the above preferences does not work = If resetting the above preferences does not work, see: * [[Finding your Firefox version]] * [[Unable to install add-ons]] * [[Websites look wrong]]

Add-ons and some websites require that you use a specific browser, and cause the following problems:

• Websites report that your browser is incompatible, or suggest that you upgrade your browser.
• You are not able to install extensions or themes from Addons.Mozilla.org because you see one of the following messages, even though your version of Firefox is listed as compatible.
  • This add-on is for older versions of Firefox
  • Upgrade Firefox to use this add-on

Note: Some websites or add-ons may be legitimately incompatible with your version of Firefox.

If you have already verified that the website or add-on is compatible with your version of Firefox, the cause of the problem may be in your Firefox "User Agent" string, that identifies your browser type to websites. Common causes of this problem are installing Megaupload Toolbar extension or Creative ZENCast plugin and then updating Firefox. This article describes how to reset your user agent to remedy these problems.

Reset your user agent

To reset your user agent:

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click Accept the Risk and Continue to go to the about:config page.
   
   
   
   
2. Search for useragent by typing it into the Filter field.
3. Right-clickHold down the control key while you click on each of the three preferences listed below and select Reset from the context menu.

• • general.useragent.extra.firefox
  • general.useragent.locale
  • general.useragent.security

1. If they exist, you may also need to reset:

• • general.useragent.extra.productName - where productName can be the name of some third party software (e.g. microsoftdotnet).
  • general.useragent.override

After resetting your user agent, you may need to clear you cookies and cache:

1. Click the menu button to open the menu panel.
2. Click History and select Clear Recent History…
3. In the Time Range to clear: drop-down, select Everything.
4. Below the drop-down menu, select both Cookies and Cache. Make sure other items you want to keep are not selected.
5. Click OKClear Now.

If resetting the above preferences does not work

If resetting the above preferences does not work, see:

• Find what version of Firefox you are using
• Unable to install add-ons (extensions or themes)
• Websites look wrong or appear differently than they should