You need to make sure that the used-space-filewalker is successfully finished for all trusted satellites, you also need to remove data of the untrusted satellites (How To Forget Untrusted Satellites).
This is mean that the filewalker is failed to complete the scan due to slowness of the disk.
Since this is Windows, then you need to stop the node, check and fix errors on the disk, then perform a defragmentation. You need also to enable an automatic defragmentation if you disabled it (it’s enabled by default). You may also disable 8.3 names: NTFS Disable 8dot3name and atime:
After that start the node again and make sure that filewalkers are not failing anymore.
You need also make sure that you do not have errors related to databases in your logs.