I've had the same problem for months (since Firefox 21 I believe) and I finally found a fix that worked for me. Here were my steps: Close Firefox. Using the firefox profile manager, create a new Firefox profile, then log into it. Install the Evernote Web Clipper add-on. Close Firefox. Copy the evernote_webclipper.sqlite file to from the new profile to the old profile (overwrite the old file). Copy the evernoteclips folder from the new profile to the old profile. In the old profile, go into the extensions folder, then look through each folder for the following folder tree: chrome > content > common > images. You can then use these images to verify that you are in the right extension folder (hint: there are a lots of elephants). Move back to the [old profile]\extensions folder and delete the folder for that extension (MAKE SURE YOU ARE DELETING ONLY THE EVERNOTE EXTENSION). In the new profile, go into the extensions folder and copy the folder for the newly installed EN web clipper (there should only be one, since that is all you installed) and paste the whole thing into the old profile extension folder. Open firefox. You should be prompted to install the web clipper, and it should work as normal from there.This is what worked for me. I am not an Evernote professional, so take these steps at your own risk, but I hope that they help you like they helped me.