OneDrive will automatically pause when a Windows PC enters battery saver mode, but if you want to stop syncing because you are on a metered or slow internet connection, you can Pause and Resume your sync.
Pausing and Resuming can also help if OneDrive status displays "Processing changes" for a long time.
To Pause syncing
Select the white or blue OneDrive cloud icon in the notification area, at the far right of the taskbar.
Note: You might need to click the Show hidden icons arrow next to the notification area to see the OneDrive icon. If the icon doesn't appear in the notification area, OneDrive might not be running. Select Start, type OneDrive in the search box, and then select OneDrive in the search results.
In the activity center, select More > Pause syncing...
Choose how long you wish to pause for: 2, 8 or 24 hours and check that the white or blue OneDrive cloud icons in the notification area show Paused.
Note: If you have both OneDrive and OneDrive for Business, you can pause and resume them independently.
To Resume syncing
Syncing will resume automatically after the Pause time has finished, or you can manually Resume syncing at any time.
Tap the paused OneDrive icon in the notification area:
In the activity center, select More again and select Resume syncing or just tap the pause button to get going again: