Large backup files require optimized storage layout formatting to prevent allocation overflows.
Specifically for or v12 users using S3-compatible repositories (like QNAP), an "overflow" can occur due to a malfunction in the object delete algorithm.
The backup or replication job fails because the data calculation fails. Common Causes of Overflow Errors in 2026 veeam backup and replication overflow error
The most common cause is backing up a virtual disk larger than using an outdated or misconfigured transport mode.
This issue often appears in the Veeam Backup & Replication console as abnormally high processing rates while jobs are running, accompanied by an error similar to "Arithmetic Overflow." Users have reported copy jobs reporting transfer rates in the hundreds of thousands of GBps, which is physically impossible. Common Causes of Overflow Errors in 2026 The
: Under high I/O, "stretch snapshots" may fail to create new file portions in time, leading to job failure. 3. SqlDateTime Overflow (Database Errors)
Enable "Hardware compression" or break the file into smaller parts using Veeam’s file-to-tape file splitting option (set to <2TB segments). leading to job failure.
: Modify the veeam.ini configuration file to increase the portionSize or change the snapshot path to a larger disk.