Error: Cannot proceed with the job: existing backup meta file 'Daily.vbm' on repository 'Daily' is not synchronized with the DB. To resolve this, run repository rescan
Is this a local hard drive on a machine or a NAS you connect to over iSCSI etc? Have you done a health check on your repository and any intermediary devices between? I'd be looking at the health of the disk and if it's an iSCSI NAS for example are you getting packet errors on your Tx and Rx and also the NAS health.
Before anyone else asks, what's your Veeam version and patch?
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Michael Paul
Veeam Data Cloud: Microsoft 365 Solution Engineer