Challenge

                    

Transform operations of a large file located on Windows Server 2012 and 2012 R2 deduplicated volume are failing with an error:
“Error: Client error The requested operation could not be completed due to a file system limitation Failed to flush file buffers. File: Filename.vbk”

                                            

Cause

                                                    

Veeam is not able to write any data to the affected file because of a NTFS limitation.
Manual un-deduplication (Expand-DedupFile) of the this file also fails with the same error.

                                                                            

Solution

                                    

Backup repository must be located on a volume formatted with the large FRS using the command “Format <Drive:> /FS:NTFS /L”

Workaround:
1. Disable Windows deduplication
2. Un-dedupe backup files: copy backup files to a temporary folder, delete original backup files and move copied files back to the original location.
3. Disable NTFS compression on backup repository volume.