Recently we found several threads that customers reported windows server backup failed with error “the version does not support this version of the file format”.
You try to backup the files and folders on a windows server 2008 R2 system, the backup target is a share folder created in a storage drive on NAS device running Linux system. After starting the backup and taking several minutes, error message will appear “the backup of volume xxx could not be completed, Error: the version does not support this version of the file format.” The backup operation stopped before completing.
Before clarify the root cause of this problem, we should first let you know a background of windows server backup
The windows backup will have problems with sparse file only in case of “File Level (Selected file/folders in a volume)” backup. For “Block Level (full volume)” backup the sparse file is not a problem and the backup/recovery would succeed. This is because for Block Level Backup the .vhd file is never mounted whereas for File Level Backup the .vhd is mounted which does not support mounting of sparse file.
Thus, we can easily get the root cause
The failure happens while the .VHD file created by Windows Backup is mounted during backup.
The .VHD file is created as a sparse file and this is not supported by the native VHD driver and hence mounting of the .VHD failed.
After some investigation, we found that the “strict allocate = yes” option of Samba will force it to not have UNIX style behavior of creating sparse file. Solution is adding “strict allocate = yes” to the smb.conf and restarting the Samba.
You can get more information about smb.conf configuration on the following link