Never run a disk defragmentation on a drive that is used for writing security video (new folder). It will never get to 100% defag. On a security video (BVR) disk that has 10% free space, will be 100% fragemented, because of the way BI and Windows allocates and writes disk files.
As an experiment I took A 4 TB WD purple disk that was 90% full with BVR video files off an old BI installation. Most of the files were between 1 amd 2.5 GB. The disk was not being used for BVR writes during the test. Windows 10 disk defrag, made 72 passes trying to def the disk. It still reported 42 % fragmented at the end for the run.
All defragmenting a Video disk will do is shorted the disk life.