We released an update for Box Drive (v2.21) with the following feature enhancements:
Enhanced Lock/Unlock for Office files [Windows] - Enhanced lock/unlock can now be enabled on Box Drive. After enabling this feature, Office files will be locked (or) unlocked when the user opens (or) closes the document. This helps improve the collaboration experience for files on Box Drive by reducing the number of conflict copies and the need to merge them.
Instructions here for enabling the feature - https://support.box.com/hc/en-us/articles/360061782454-Enabling-Enhanced-Lock-Unlock-on-Box-Drive