I recently installed Qt 5.13.0 and its MaintenanceTool (MaintenanceTool.exe). The default repositories were working, but after one day, the MaintenanceTool
suddenly reports that no repositories were set. It seems some bugs of Qt MaintenanceTool.

The Maintenance Tool is doing crazy things since the recent updates made by Qt team. The only solution I know is:
- Add the next temporary repository or user defined repositories in “Settings”
- Add repository url in repository tab and verify you can access the repository.
- For Windows: http://download.qt-project.org/online/qtsdkrepository/windows_x86/root/qt/
- For Mac: http://download.qt-project.org/online/qtsdkrepository/mac_x64/root/qt/

Now, you can update the Qt components and you should see a new update for the Maintenance Tool.