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Fix slowness, crashing, error messages and other problems

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When Firefox connects to a secure website (the URL begins with "https://"), it must verify that the certificate presented by the website is valid and that the encryption is strong enough to adequately protect your privacy. If the certificate cannot be validated or if the encryption
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On websites which are supposed to be secure (the URL begins with "https://"), Firefox must verify that the certificate presented by the website is valid. If the certificate cannot be validated, Firefox will stop the connection to the website and show a "Your connection
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Certificates used by websites which are considered to be secure (their URL begins with "https://") are only issued for a certain period of time. If a website presents a certificate with a validity period that doesn't match the current value of your system's clock,
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If Firefox can't access a secure site (one that starts with https) you will see an error page with the heading Secure Connection Failed and a message about the error. If you see this heading without accessing a secure site, see Troubleshoot extensions, themes and hardware acceleration
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Accessibility features are not yet fully supported in multiprocess Firefox. If third-party software (screen readers, Windows touchscreen software or anti-spyware) requests access to Firefox's accessibility features, Firefox limits this access to web content to prevent stability
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Support will end for all NPAPI plugins except for Flash in March 2017, when Firefox version 52 is released. See this compatibility document and this article for details. Beginning with Firefox version 52, support has ended for all NPAPI plugins except for Adobe Flash. See this
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A crash is what happens when Firefox closes or quits unexpectedly. After a crash, you should see the Mozilla Crash Reporter appear. This article will help you fix crashes and show you how to get more help if you're having difficulties. Note: If Firefox is open but won't respond
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Firefox may give you a "Warning: Unresponsive script" prompt that says "A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete." This article describes why this could
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The Firefox Health Report provides you with information about your browser’s performance and stability over time. Mozilla uses this data to provide you with meaningful comparisons and tips. We also aggregate the data shared by everyone to make Firefox better for you. Note: This applies
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This article describes how to troubleshoot printing problems in Firefox. For general information on printing in Firefox, see How to print web pages in Firefox. Table of Contents1 Check Firefox page settings2 Check Firefox page settings3 Check other browsers and printers4 Reset
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If you see a "Profile Missing" error message that says, Your Firefox profile cannot be loaded. It may be missing or inaccessible it usually means that Firefox can't find or access the profile folder. This article explains what to do if you see this error.
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Firefox may repeatedly open new, empty tabs or windows after you click on a link, forcing you to close Firefox. The same untitled tabs or blank windows may open the next time you start Firefox if the previous session is restored. This usually happens because you chose Firefox
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A crash is what happens when Firefox closes or quits unexpectedly and the Mozilla Crash Reporter appears. If Firefox keeps crashing when you open it, this article will show you how to get it working again. Other problems with crashing: If Firefox starts without crashing but then
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REDIRECT What does "Your connection is not secure" mean?
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Starting in Firefox 34, Secure Sockets Layer version 3.0 (SSLv3) is blocked by default because it is no longer secure (for details, see this blog post). If you see an error message, "Unable to connect securely" when you visit a website, see the article What do the SSLv3
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All of your personal settings, bookmarks, and other information are kept in your Firefox profile. Firefox needs an unlocked profile to start up, and if the profile is locked, it displays the message, Firefox is already running, but is not respondingA copy of Firefox is already open.
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Mac and Linux users: This article applies to Windows only. Some third-party software providers might change Firefox's shortcut so that the browser always opens their page. To prevent this from happening, make sure you decline any options to set your site preferences when installing
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There's never a good time for a crash, and when Firefox crashes in the middle of something important it can be really frustrating. Luckily, we've got some easy things you can do to avoid crashes and keep Firefox running in tip-top shape. For the tech savvy, we've got articles
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This article shows you what to do if you cannot add new bookmarks or make other changes to your bookmarks. Note: If you have been able to save bookmarks but they are now missing, see Recover lost or missing Bookmarks. Table of Contents1 I can't add or change bookmarks2 I can
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Firefox includes a Software Update feature that automatically checks for updates and prompts you to install them when necessary. For more information about the Software Update feature, see Update Firefox to the latest version. Sometimes, the updater fails and displays an Update
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