ERROR_INC_BACKUP - 4003 (0xFA3)
The backup failed. Was a full backup done before?
Updated: Feb 21, 2026
Technical Meaning
The ERROR_INC_BACKUP error indicates that a backup operation failed because a full backup was not performed before the current attempt. This error suggests that the system is unable to perform incremental backups without a previous full backup.
Error Details
This error code, 4003 (0xFA3), is returned by Windows APIs when an incremental backup fails due to the absence of a recent full backup. Incremental backups rely on having a baseline from which changes can be recorded and saved.
Usage Context
Incremental backups are commonly used in scenarios where frequent updates or modifications occur, allowing for smaller data transfers compared to full backups. However, these methods require a previous full backup to function correctly.
Developer Interpretation
Developers should interpret this error as an indication that the system is unable to proceed with the requested incremental backup operation. This could be due to the lack of a recent or any full backup being available in the system's history.
Related Errors
ERROR_NO_BACKUP(0x80070541): Indicates no backup was found at all, not just an incomplete one.ERROR_BACKUP_CONTROLLER(0x8007063A): Suggests a problem with the backup controller or service.
FAQ
Q: Can this error be resolved by performing a full backup?
Yes, performing a full backup before attempting incremental backups will resolve this issue. Incremental backups require a baseline created by a full backup to function correctly.
Q: What are some common causes of this error?
The most likely cause is the absence of a recent or any full backup in the system's history. Other potential issues could include incorrect usage context, such as attempting an incremental backup on a directory that has not been backed up before.
Summary
The ERROR_INC_BACKUP error code (4003) signifies that a full backup was not performed before an attempt to perform an incremental backup. Developers should ensure that a full backup is available before initiating any incremental backups to avoid this error.