No idea why it did that. I am sure they are there just not working. https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data see if can grab them Have you looked in Add/Remove Programs to see if still listed there ? Please uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. Reinstall with Current Release Firefox 57.0.1 with a Full Version Installer https://www.mozilla.org/firefox/all/ Please let us know if this solved your issue or if need further assistance.

Look on your desktop. Do you see a folder called; '''Old Firefox?''' https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible