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How do I get AC_RunActiveContent.js?


The website listed below brings up a panel that says "This page requires AC_RunActiveContent.js." and won't run.

Additional System Details

Sites Affected


Installed Plug-ins

  • Shockwave Flash 10.3 r181
  • iTunes Detector Plug-in
  • Next Generation Java Plug-in 1.6.0_26 for Mozilla browsers
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • 4.0.60531.0
  • The plug-in allows you to open and edit files using Microsoft Office applications
  • Adobe PDF Plug-In For Firefox and Netscape 10.1.0
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.


  • User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:5.0) Gecko/20100101 Firefox/5.0

More Information

Have updated firefox from v4 to v5, then uninstalled and reinstalled firefox v5, updated plugins, installed latest adobe reader, etc, nothing helps. Adobe flash site confirms latest flash player installed and working. This site works fine with IE and with IE and firefox on another machine, used to work on this machine but stopped, this machine is a new sony viao running windows 7 -64bit home premium. Spent hours on chat with sony help. What else is there to try? This is my daughter's homework site. She prefers firefox but I can't make it work.

  • Top 10 Contributor
  • Moderator
10784 solutions 97065 answers

Clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

  • Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now"

"Remove Cookies" from sites causing problems:

  • Tools > Options > Privacy > Cookies: "Show Cookies"

Start Firefox in Troubleshoot Firefox issues using Safe Mode to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

Question owner

Clearing the cache fixed it. Didn't have to mess with the cookies. Thank you very much. I couldn't imagine that the cache would cause such behavior.

  • Top 10 Contributor
  • Moderator
10784 solutions 97065 answers

You're welcome

You may have had a corrupted file AC_RunActiveContent.js in the cache that was working.

First to try is always to reload and bypass the cache in case of unexplained problems.

Reload web page(s) and bypass the cache.

  • Press and hold Shift and left-click the Reload button.
  • Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
  • Press "Cmd + Shift + R" (MAC)