How to diagnose a problem with the windows 2012 r2 file system?

Question

Windows Server

There is a VM with win2012r2. The file server role is deployed on the VM, some anomalies have now begun to occur. Permissions for some files have been lost, and when large files are deleted, the free space does not change.

Answer 1

Always do a chkdsk first:
This is the first step for this kind of diagnosis.

Answer 2

Volume Shadow Copy Information: Cannot start COM server with CLSID a bunch of these errors.
chkdsk : We have found errors on this disk, Please restore it to avoid data loss.
I did chkdsk, and things are still there. It is not clear where the free space goes and they do not work correctly on the right.
Free space is eaten off by 1 GB per day, why it is not clear.