Hey Marcelo! Sorry to hear that. Remove Thunderbird's program files and then reinstall Thunderbird. Please follow these steps: #Download the latest version of Thunderbird from http://www.mozilla.org/en-US/thunderbird/ and save the setup file to your computer. #After the download is complete, close all Thunderbird windows (Click Exit/Quit from the menu button on the right). #Delete the Thunderbird installation folder, which is located in one of these locations, by default: #*'''Windows:''' #** C:\Program Files\Mozilla Thunderbird\ #** C:\Program Files (x86)\Mozilla Thunderbird\ #*'''Mac:''' Delete Thunderbird from the Applications folder. #*'''Linux:''' If you installed Thunderbird with the distro-based package manager, you should use the same way to uninstall it - see [[Installing Thunderbird on Linux]]. If you downloaded and installed the binary package from the [http://www.mozilla.org/en-US/thunderbird/ Thunderbird Download Page], simply remove the folder ''thunderbird'' in your home directory. #Now, go ahead and reinstall Thunderbird: ##Double-click the downloaded installation file and go through the steps of the installation wizard. ##Once the wizard is finished, choose to open Thunderbird after clicking the Finish button. <b>WARNING:</b> Do not run Thunderbird's uninstaller or use a third party remover as part of this process, because that could permanently delete your Thunderbird data, including but not limited to, extensions, emails, personal settings and saved passwords. <u>These cannot be recovered unless they have been backed up to an external device!</u> Please report back to see if this helped you! Thank you.