Backup Failure - Error code : 41, 3, 1060, 26

Hi, our company is using Acronis.11
When progress reached as 20% during backup, this error appeared and stopped.
Could you let us know what can be root cause of this failure?
Especially, Error code : 26 "Invalid file reference"
Error Code: 41
Module: 307
LineInfo: e6792a5ee190dd9e
Fields: $module : agent_protection_addon_vs
Message: ProtectCommand: Failed to execute the command.
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Error code: 3
Module: 329
LineInfo: 1cd98aae889424f9
Fields: $module : disk_bundle_vs
Message: Backup has failed.
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Error code: 1060
Module: 1
LineInfo: b43e776571144dee
Fields: $module : disk_bundle_vs
Message: Failed to commit operations.
Errorcode: 26
Module:7
line Info: 89d94b01b483e29e
Fields: $module : disk_bundle_vs
Message: Invalid file reference.
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Best regards,
Ekaterina Surkova | Forum Moderator
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