Windows backup fails with no sufficient free space on target volume in Windows Server 2012

View products that this article applies to.

Symptoms

When this issue occurs, the system indicates that the target volume doesn't have sufficient free space, even though it actually has.

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Cause

This issue occurs because the Wbengine.exe service estimates the number of bytes that are needed to perform a backup incorrectly. The Wbengine.exe service loops through each partition of a disk, counting and accumulating the total bytes and free space. However, it doesn't accumulate the number of excluded bytes across each partition. Therefore, it incorrectly use the number of excluded bytes of the last partition checked in calculations. In this scenario, if there are enough ignored excluded bytes in the previous partitions, this can cause the check to fail even though there's sufficient space for a backup.

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Hotfix information

Important If you install a language pack after you install this hotfix, you must reinstall this hotfix. Therefore, we recommend that you install any language packs that you need before you install this hotfix. For more information, see Add language packs to Windows.

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that's described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there's a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section doesn't appear, submit a request to Microsoft Customer Service and Support to get the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that don't qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website:

http://support.microsoft.com/contactus/?ws=support

Note The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you don't see your language, it's because a hotfix isn't available for that language.

Prerequisites

There's no prerequisite to apply this hotfix.

Registry information

To use the hotfix in this package, you don't have to make any changes to the registry.

Restart requirement

You may have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix doesn't replace a previously released hotfix.

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File Information

The English (United States) version of this software update installs files that have the attributes that are listed in the following tables. The dates and times for these files are listed in Coordinated Universal Time (UTC). Be aware that dates and times for these files on your local computer are displayed in your local time and with your current daylight saving time bias. The dates and times may also change when you perform certain operations on the files.

Windows 8 and Windows Server 2012

Notes

The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
Version Product Milestone Service branch
6.2.920 0.17xxx Windows 8, Windows RT, or Windows Server 2012 RTM GDR
6.2.920 0.21xxx Windows 8, Windows RT, or Windows Server 2012 RTM LDR
GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.
The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed in the "Additional file information" section. MUM, MANIFEST, and the associated security catalog (.cat) files, are very important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

Version	Product	Milestone	Service branch
6.2.920 0.17xxx	Windows 8, Windows RT, or Windows Server 2012	RTM	GDR
6.2.920 0.21xxx	Windows 8, Windows RT, or Windows Server 2012	RTM	LDR

x86 Windows 8

File name	File version	File size	Date	Time	Platform
Wbengine.exe	6.2.9200.21653	1,351,680	07-Oct-2015	13:32	x86

x64 Windows 8 and Windows Server 2012

File name	File version	File size	Date	Time	Platform
Wbengine.exe	6.2.9200.21653	1,618,944	07-Oct-2015	13:29	x64

Additional file information

x86 Windows 8

File property	Value
File name	Update.mum
File version	Not applicable
File size	1,947
Date (UTC)	08-Oct-2015
Time (UTC)	18:29
Platform	Not applicable

File name	X86_ec027fb0f7c34bba8fcc86001c0eceb5_31bf3856ad364e35_6.2.9200.21653_none_a8548e52f200fe02.manifest
File version	Not applicable
File size	703
Date (UTC)	08-Oct-2015
Time (UTC)	18:29
Platform	Not applicable

File name	X86_microsoft-windows-blb-engine-main_31bf3856ad364e35_6.2.9200.21653_none_e135fb21ea2cf429.manifest
File version	Not applicable
File size	8,049
Date (UTC)	07-Oct-2015
Time (UTC)	14:10
Platform	Not applicable

x64 Windows 8 and Windows Server 2012

File property	Value
File name	Amd64_9b856194058bd880960005cdb612ea75_31bf3856ad364e35_6.2.9200.21653_none_bbd0b79e80766824.manifest
File version	Not applicable
File size	707
Date (UTC)	08-Oct-2015
Time (UTC)	18:29
Platform	Not applicable

File name	Amd64_microsoft-windows-blb-engine-main_31bf3856ad364e35_6.2.9200.21653_none_3d5496a5a28a655f.manifest
File version	Not applicable
File size	8,055
Date (UTC)	07-Oct-2015
Time (UTC)	15:26
Platform	Not applicable

File name	Update.mum
File version	Not applicable
File size	2,152
Date (UTC)	08-Oct-2015
Time (UTC)	18:29
Platform	Not applicable