If none of the above works, VSS system files may be corrupted.
On the backup source server:
cd /d %windir%\system32
net stop vss
net stop swprv
regsvr32 /s ole32.dll
regsvr32 /s vss_ps.dll
vssvc /register
regsvr32 /s /i swprv.dll
regsvr32 /s es.dll
regsvr32 /s stdprov.dll
regsvr32 /s vssui.dll
net start vss
net start swprv
Reboot and re-test.
0xe00086cc corresponds to:
"The media server was unable to mount the storage device because the device name may be missing or invalid, or the device may be offline or not ready."
In human terms: Backup Exec cannot access the backup storage device (tape drive, disk folder, deduplication folder, etc.) during a backup or restore job. 0xe00086cc backup exec
The "helpful feature" implied by this error is the Synchronization process between the Backup Exec server and the Virtual Machine Manager (VMware vCenter or Hyper-V host).
Check Network Connectivity:
Ensure Resource Availability:
Review Backup Job Configuration:
Logs and Detailed Error Messages:
Update and Patch Backup Exec:
The most frequent cause of 0xe00086cc is simply using the wrong credentials.
Action: Create a dedicated service account for backups, add it to BUILTIN\Administrators and BUILTIN\Backup Operators, then reassign it to the affected backup job.
A full or corrupted shadow storage area can cause I/O write failures.
On the failing volume (e.g., C:):
vssadmin delete shadows /for=C: /all
vssadmin resize shadowstorage /for=C: /on=C: /maxsize=10GB
Warning: Deleting shadows removes existing restore points. This is safe for backup servers but ensure you don’t need local shadow copies for restore.
After resizing, rerun the backup job.
Error code 0xe00086cc is a VSS (Volume Shadow Copy Service) related failure. The full error message often reads:
"VSS reported an error. The I/O writes have failed. Check the Windows Event Viewer for more details. Access is denied."
In technical terms, the error translates to VSS_E_ACCESS_DENIED (0x8004230C). This indicates that Backup Exec’s AOFO (Advanced Open File Option) or the VSS infrastructure was unable to read one or more volumes on the target machine because the process lacked the necessary permissions. If none of the above works, VSS system