onedrive showing showing a blue & grey icon in notification area at boot up, why ?

I'm seeking some information as to why when my windows desktop computer is booting up and the reaches the desktop and the desired notification icons are loaded there I'm currently seeing a blue one drive icon plus a gray icon, the blue icon only appears for a few seconds and then disappears.

Yeah I wondered about that. The icon is identical to the icon you get if you use the BT cloud service (major UK ISP) which I did until recently, until I ditched them as getting too expensive. I thought it was that and got it a couple of times but not seen it recently.

When OneDrive loads, a gray and white cloud icon appears with a blue circle embedded in the cloud. The blue circle indicates that OneDrive is in the process of synchronizing local OneDrive files with cloud OneDrive. The length of time the blue circle appears is in proportion to how many files are being synchronized and the speed of your Internet. After synchronization, the blue circle disappears.