Incremental backups of the VM may fail if the NTFS file system in the guest OS is corrupted and the backup uses MSDP storage

This error may occur in the following case:

The VMware or Hyper-V backup policy specifies Media Server Deduplication Pool (MSDP) storage.
The backup schedule includes incrementals (differential or cumulative).
The NTFS file system in the VM's guest OS is corrupted. For example, the file system contains orphaned file record segments. The bptm debug log contains messages similar to the following:
```
16:24:04.604 [5720.7068] <16> 6:bptm:5720:win2012-2.hrous.sen.com: 
[ERROR] PDSTS: fbu_fill_bitmap: (1945) stream_offset(610848768) 
+ length(8192) > (1946) stream_offset(610848768)
16:24:04.604 [5720.7068] <16> 6:bptm:5720:win2012-2.hrous.sen.com: 
[ERROR] PDSTS: fbu_scan_buf: fbu_fill_bitmap() failed 
(2060022:software error)
```
The incremental backups fail with status 84, media write error.
Use the chkdsk command to examine the file system in the guest OS and repair it as needed. Then restart the VM and rerun the backup.