EV Mailbox Tasks failed

After Many of Troublshooting and using DebugDiag tool from Microsoft to monitore the ArchiveTask.exe, we found that the issue of failing tasks is solved by RemoveEmbeddedAttachments key, on the EV server.same.

Follow the below steps has been solved My Issue.

1. Go to Regedit.
2. On 32-bit servers, expand HKEY_LOCAL_MACHINE\SOFTWARE\KVS\Enterprise Vault\Agents.

    On 64-bit servers, expand HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\KVS\Enterprise Vault\Agents.
3. Right-click on Agents and choose New > DWORD Value.
4. Enter RemoveEmbeddedAttachments for the Name and give it a decimal value of 0.
5. Restart the archiving tasks.

This setting will allow the message to be archived without the error occurring in the Event Viewer log.
NOTE: The embedded attachments will continue to be archived with this setting in place.