This article explains what steps to take if your clipboard stops working. The clipboard is the copy/paste/cut function.

Clipboard never works

If the clipboard never works, you might be infected with malware. If the clipboard never works, even with Firefox closed, it is not a Firefox problem. Firefox does not allow and even prevents your computer from getting malware. If the clipboard never works only when Firefox is open, proceed to the next section.

Malware

Malware (malicious software) can prevent the clipboard from working. Some malware that causes the clipboard to never work are:

• pushow
• New.net

New.net is an extension that comes with certain software, including:

• • RealNetworks (RealOne Player)
  • Babylon
  • BikiniDesk
  • Cydoor (LingoWare)
  • gDivx
  • Go!Zilla
  • Grokster
  • iMesh
  • KaZaA
  • Mindset Interactive (NetPalNow)"
  • Mp3.com
  • RadLight / Subtitle Studio
  • UK Software
  • Webshots

Uninstall the New.net extension, if it is installed. For help, see Disable or remove Add-ons.

Also download and install Malwarebytes' Anti-Malware to scan your computer for malware. Another option is to visit a forum specializing in malware removal, such as one of the forums listed here.

Clipboard sometimes works

Update Firefox

If you do not have the current version of Firefox you need to update. For help, see Update Firefox to the latest release.

JavaScript

Some websites can disable or replace context menus. To disable this, see JavaScript settings and preferences for interactive web pages.

Rich-Text editors (gmail/yahoo)

Some Rich-Text Editors have copy and paste buttons that override this feature. This is because of security reasons, Mozilla does not want any sensitive information being pasted and than submitted without your permission.

Other Solutions

If none of these solutions worked, try Troubleshoot and diagnose Firefox problems

Based on information from Clipboard not working (mozillaZine KB)