By AOMEI / Last update September 14, 2020

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The case

"I am trying to get a Windows Server 2012 box to backup to a NAS. However, Windows Server backup failed every time no matter what I select to backup (System State, BMR, single file, etc), the job will fail giving an Incorrect Function error. Can anybody give some insight into what could be causing the Incorrect Function error?"

Windows Server Backup Incorrect Function

Reasons and solutions for Windows Server Backup incorrect function

Sometimes, you may meet this situation. You receive the following error code when you try to back up files or folders by using Windows Server Backup: the backup process started but then failed with Windows Server Backup “Incorrect Function” and “There was a failure in preparing the backups image of one of the volume”.

What’s wrong with it and how to fix this? Let’s see the reason and solutions for this issue.


1. The issue occurs because the folders or libraries that you are trying to back up or restore include a reparse point. A file or directory can contain a reparse point, which is a collection of user-defined data. A reparse point may be used to point to a file that is temporarily relocated on a different drive. For example, a reparse point would allow a folder such as C:\DVD to point to Drive E, the actual DVD drive.

If the reparse point points to a volume that uses the FAT file system, it will cause this issue.

2. Windows Backup sometimes fails to read the last sector on the volume. You may receive windows server backup error incorrect function if the last sector is corrupted.


To deal with Windows Server Backup completed with warnings incorrect function caused by reason 1, you should remove the reparse point from the library, and then create a backup again. To back up content for this reparse point (in this case, the FAT volume or the mounted volume), select the absolute path of this location in the Windows Backup configuration user interface.

First, you should know where the reparse point folder is. To locate reparse point folder or its subfolder, do as the following.

1. Click Start button, type CMD in the Search program and files box and then press Enter.

2. In the Command Prompt window, type DIR /AL /S and then press Enter. The list of JUNCTION (one type of reparse point) list is displayed.

Command Prompt

Note: You see several entries that say "junction" and the location to that the entries point. Junction point is another name for reparse point. When a program tries to write to a directory that is really a reparse point, those files are sent completely blindly to the other directory instead.

After you find reparse point, delete it. To delete mounted volume reparse point, follow these steps:

1. Locate the reparse point you found, right-click it and select Properties.

2. In the General tab, confirm the folder Type is Mounted Volume and then delete this folder.

Mounted Volume

To deal with Windows Server Backup failed to complete incorrect function caused by reason 2, you can try to shrink the volume, whose backup is failing, by several MBs. Do as the following steps to shrink volume.

1. Press Win+R and type “diskmgmt.msc” to open disk management. Right-click the volume you need to shrink and select Shrink volume.

Shrink Volume

2. Enter the amount of space to shrink in MB and click Shrink.

An easy way to solve Windows Server backup incorrect function

If the solution mentioned above does not solve the problem, or you think the solutions are complicated, you can try an easier solution – use third-party software. As a matter of fact, Windows Server Backup still leaves something to be satisfied.

When you try to backup using Windows Server Backup, you cannot use any volumes not formatted with NTFS as backup source or backup target. Besides, Windows Server Backup in 2008/2008 R2 cannot support volume greater than 2TB.

If you want to find an easy way to solve those issues, you can turn to AOMEI Backupper.

Powerful Windows Server backup software - AOMEI Backupper Server

AOMEI Backupper Server is a professional Windows Server backup and recovery software. With it, you can backup files and folder, partitions, hard disk or only system very easily. Compared to Windows Server Backup, it offers more powerful functions.

  • It allows you to backup file size large than 2 TB. Also, it supports both NTFS and FAT32 File System.

  • You can set scheduled backup to backup at a pre-set time automatically: daily/weekly/monthly/event triggers.

  • Besides full backup, it also supports incremental and differential backup types that can help save storage space.

If anything bad happens to your system or data, AOMEI Backupper allows you to restore your computer to its previous state with just a few clicks. You can even restore system to dissimilar hardware.

How to backup Windows Server with AOMEI Backupper

Step 1. Download AOMEI Backupper, and launch this software. It will bring you to the main interface.

Download Free Trial Win 10/8.1/8/7 & Server
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Step 2. Click Backup at the left panel, and choose System Backup.

System Backup

Step 3. You do not have to choose source partitions, AOMEI Backupper has chosen them automatically. Just click the column below to select another location as the destination path to store your system image files. The destination location can be verified like internal hard drive, external hard drive and NAS.

Start Backup

▶ Options: you can encrypt your backup and enable email notification, etc.
▶ Schedule: you can create automatic backup tasks. There are six schedule modes available: “Daily”, “Weekly”, “Monthly”, “Event triggers”, and “USB plug in”.
Scheme: you can enable Disk Space Management that can help automatically delete the previous backup images.

Step 4. Finally, click Start Backup to confirm.


That’s all for how to fix Windows Server 2012/2008/2016 backup incorrect function error. If the two methods cannot help you solve the problem, you can try the Windows Server Backup alternative - AOMEI Backupper Server. With the help of AOMEI Backupper, you can backup and restore in a few clicks and do not have to worry Windows Server Backup incorrect function issue anymore.

And if you want to protect unlimited PCs and servers within your company, you may choose AOMEI Backupper Technician Plus. It offers unlimited billable technical services to clients. It also enables you to copy installation directory for portable version creation.