Please consider turning on send info to Mozilla from with in Firefox before posting a question. This helps us help you. I have no info from your system that would help see things that cause issues. So am guessing. You also did not provide enough information like if using Spanish version or English version what language packs you have installed. uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files , C:\Program Files(x86) & C:\ProgramData Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do : *https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles *https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer Reinstall with Current Release Firefox 59.0.1 with a Full Version Installer *https://www.mozilla.org/firefox/all/ Pick the language of your choice there : If still issues : it is your Profile : Make a new one and test ...: *https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles If is your Profile : *https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox Note: Any customization will revert back to default, you will also need to reinstall Extensions. Please let us know if this solved your issue or if need further assistance Please let us know if this solved your issue or if need further assistance.