Hello everyone!
Veeam 12.3.2.3617, Community Edition, Workstation Backup by veeam agent
I’m having an issue with one of my home PCs. When I try to back it up, an error appears.
29.09.2025 21:31:17 :: Error: Unable to resend traffic block '15863' because traffic history doesn't contain this block. History low block id '15869'.
Failed to upload disk. Skipped arguments: [EmulatedDiskSpec>];
Agent failed to process method {DataTransfer.SyncDisk}.
Exception from server: There is no traffic block '15863' on the source side.
Unable to retrieve next block transmission command. Number of already processed blocks: [25496].
Failed to download disk 'bdd448f6-e7b0-4f2b-93b3-6eb675ad51c3'
Backups of two other PCs to the same storage complete without any problems. What could be causing this behavior?
I tried replacing the target HDD — it didn’t help; the error can also appear when backing up the SSD (the drive’s health is normal, no errors).
I tried different backup types (volume, file-level, entire PC) — that didn’t help either.
I tried recreating the backup job — no change.
