VR Mocap Studio automatically saves the binding between the trackers and the skeletal bones after basic and manual calibrations. However, after reloading, SteamVR changes ID’s of all tracked devices. This makes it difficult to automatically restore the calibration.
Select skeletal mesh and preset that has already been calibrated before. Put on trackers, place controllers near you, if they are needed. Put the headset on if Capture in Headset mode was checked. Then press Refresh button.
Then stand in the T-pose by stretching the arms to the sides parallel to the floor. Wait till the countdown of the timer. The bindings between trackers and the bones will be restored, and the window for animation capture will become available.