You perform Backup to VD or Copy Hard Disk operations, and get the following error:
Error: 69923 (0x11123)
VSS specific error: The VSS provider cannot perform the operation because there is not enough disk space.
Please see the system and application event logs for more information.
This error appears because there’s not enough space to create VSS snapshot on one of involved partitions, such as vendor/recovery partitions about 100-200 MB in size.
Note: this solution does not apply to source objects currently in use, such as partition with loaded operating system.