How to Fix the Firefox "EM Is Not a Function" Error
- 1). Navigate to the Firefox Plugin Check Web page (see Resources) and wait for the browser to automatically detect which plugins are outdated. Click the yellow or red "Update" button next to the first plugin that needs to be updated. Click "Download Now" and "Save File."
- 2). Navigate to the folder where your downloaded files are saved and double-click the plugin installation file you downloaded. Click "Next" at each prompt, then click "Finish" to update the plugin. Repeat the entire process with each outdated plugin listed on the Plugin Check page.
- 3). Close and then re-open Firefox and see if the error message continues to occur. Click the "Tools" menu if the problem hasn't been resolved, then click "Add-Ons" to open the "Add-Ons Manager" tab.
- 4). Click the black circle icon located at the upper right corner of the screen and click "Check For Updates." Click "Next" and "OK" to install any updates found. If the error message is still being displayed, go to the next Step.
- 5). Return to the "Add-Ons Manager" tab and click the "Extensions" button at the left side of the screen. Locate the most recent add-on you have installed in the list of add-ons. Click the "Disable" button to the left of the add-on's name, then click the blue "Restart" link.
- 6). Repeat the process of disabling each add-on until the error message goes away to determine which add-on is causing the problem. Return to the "Add-Ons Manager" tab and click the "Enable" button next to each of the add-ons that didn't cause the error message.
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