User Tools

Site Tools


Ahsay Backup Software

Backup Set Types

Supported Storage

Features in OBM / ACB

Features in CBS

Brand and Customize



FAQs and Known Issues

Can't Find What You Need?


ISSUE: VSS_E_FLUSH_WRITES_TIMEOUT (MS Exchange server backup)

Article ID: 5348
Reviewed: 18/07/2018

Product Version:
AhsayOBM : or above
OS: Windows

Problem Description

When performing a MS Exchange server backup, the following error message is received in the backup report:

No. Type Timestamp Log
* ... ... ...
* info ... Finished running pre-commands
* info ... ...
* ... ... ...


The message suggests that VSS was unable to create the image in time for the backup.


To resolve the issue, check if there is other I/O intensive application(s) that is running on the client computer at the time of the backup. Try adjusting the backup schedule to another time when disk usage is low.

Check on the VSS writers:

  • Open an Administrative command prompt and enter the following command:

    vssadmin list writers
    This should output a list of writers and their status, they should all be reported as stable.

    If there is writer listed at unstable, re-register the Volume Shadow Copy Service by following the instructions below:

    • In an administrative command prompt, browse to ${OBM-Install-Home}\bin
    • Execute the 'RegisterVSS.bat' batch file.
    • Reboot the machine.
Ensure that left-over snapshots are cleaned up:

  • Enter the following command in an elevated command prompt:

    vssadmin delete shadows /all
    This will clean up all VSS snapshots.

    Defect operating system may often accumulate hundreds of VSS snapshots that persist in the system and cause Windows to become un-responsive.
In some case, you may not be able to delete the VSS snapshots with the above command. Perform the following instead:

  • To decrease the maximum shadow storage size, enter the following command in an elevated command prompt:

    vssadmin resize ShadowStorage /For=C: /On=C: /MaxSize=300MB
    If there is no VSS writer error displayed, but the system is not creating a new VSS snapshot, increase the max shadow storage size on the system instead.

  • To increase the maximum shadow storage, enter the following command in an elevated command prompt:

    vssadmin resize ShadowStorage /For=C: /On=C: /MaxSize=10GB


obm, exch, exchange, vss, timeout, flush, VSS_E_FLUSH_WRITES_TIMEOUT

public/5348_vss_e_flush_writes_timeout_during_exchange_server_backup.txt · Last modified: 2018/07/19 14:09 by edward.chan