There are several ways that SpiderOak One or Groups can be launched automatically on Windows, the first two of which are under our the application's control but the others are not:
The setting Preferences - General - Launch SpiderOak at OS Startup is our control for this. If it is enabled, disable it. If it is disabled, then enable it temporarily, close and reopen the backup application, and now disable it.
The setting Preferences - General - Enable OS Integration provides right-click access to the backup application in Windows' file explorer. Under some circumstances, having this option enabled might cause Windows to launch the application in an apparently random manner. So if it is enabled, disable it. If it is disabled, then enable it temporarily, close and reopen the application, and now disable it.
The Task Manager in Windows or any number of third party utilities may be calling the application, either through their GUI interfaces or directly via a change they made to the Windows Registry. Note that clearing the above settings in the backup application cannot stop the Task Manager or third party tools from launching it. Make sure that the Task Manager and any utilities do not reference SpiderOak One or Groups.
If your workplace, school, or organization installed SpiderOak One or Groups for you, the system administrator may have overridden any of the above. You will need to speak with your IT support staff in this case.
Something may have gone wrong in your installation of Windows. In that case the backup application is being launched by one or another Windows setting outside our control and you will have to use a Windows configuration tool to find and disable the offending setting. CCleaner is a popular tool for this task.