Error Message

Backup Exec job log reports:
Error - 0xe00084f4 - An unknown error has occurred.

Windows Event Viewed reports:
Event ID: 1450
Insufficient system resources exist to complete the requested service. - Delayed Write Failed Windows was unable to save all the data for the file . The data has been lost.

OR

Final Error : 0xe00084f4 - An unknown error has occurred.
Backup \\Servername\
Storage Device "Backup to Disk Folder 0001" reported an error on request to write data to media.

Error reported :
The process cannot access the file because it's being used by another process.
V-79-57344-34036 - An unknown error has occurred

UMI Code: V-379-57665

The issue can occur if a large backup to disk file size is used and the server is not able to write that size without errors.

OR

Backup to Disk Folder is offline or running out of free space.

Solution 1:

1. Make sure that Backup to Disk folder is online and not running out of free space.
    
2. In case it is on a remote Backup to Disk folder, make sure it is accessible using UNC path.

Solution 2:

Reduce the backup to disk file size by going to the backup to disk folder Properties and Maximum Size For Backup To Disk Files.

Solution 3:

In case backup job is targeted to a Removable B2D that resides on external USB hard drive or Removable Disk Storage like Dell Power Vault RD1000, Follow the steps:

1. Plug the USB drive to rear USB port on the media server in case it is plugged into front USB port.
    
2. Check if there is Windows Delayed Write Failed error has occured in Windows Event Viewer when backup job was running.
    
3. Following application window may popup in the System Tray :
   
   Windows - Delayed Write Failed : Windows was unable to save all the data for the file name_of_the_file_you_want_to_save. The data has been lost.
   
   This error may be caused by a failure of your computer hardware or network connection. Please try to save this file elsewhere
    
4. Turn off "Enable Write Caching on the Disk". from
   My Computer > (right-click) your disk > Properties > (tab) Hardware > (button) Properties > (tab) Policies > (take the check mark out of) "Enable Write Caching on the Disk"Reboot the media server.                                         or for Server 2016 OS and later:                                                                                                                                                                                                                                                                                                                        This PC > (right click) backup disk > Properties > (tab) Hardware > highlight disk > (button) Properties > (tab) Policies > (take the check mark out of) "Enable Write Caching on the Device" if present. 
5. Reboot the Backup Exec server             
6. Run the backup job again.
    
7. If this doesn't work then disable/delete the USB drive disk storage in Backup Exec and delete the changer.cfg and folder.cfg file from the BEData folder.
    
8. Create a new removable B2D
    
9. Restart the Backup Exec services.