This article will give the steps to silently uninstall from a machine.
Windows Silent Uninstallation
1) Search for cmd in programs.
2) Right-click the cmd icon in the search field.
3) Choose Run as Administrator. This is necessary for the uninstall to complete.
4) Run the command:
"C:\Program Files (x86)\Backblaze\bzdoinstall.exe" -douninstall -nogui
Mac Silent Uninstallation
1) Go to https://secure.backblaze.com/update.htm
2) Download the Mac installer.
3) Mount the DMG.
4) Open Terminal and run this command:
sudo /Volumes/Backblaze\ Installer/Backblaze\ Uninstaller.app/Contents/MacOS/Backblaze\ Uninstaller
Terminal will request the Admin password for that computer before executing.
Please note that at this time, a dialog box will still appear asking to confirm uninstallation.