.SPI File Extension
File TypeShadowProtect Incremental Backup File
What is an SPI file?
Backup file created by ShadowProtect, a program used for creating backups and performing disaster recoveries; contains the changed file contents since the last backup performed.
SPI files are used to reduce the size of overall backup files by storing only the files that have changed. They are combined with previously-created SPI files when performing a complete restore.
NOTE: Full backups are created using .SPF files.