You can configure Backup settings as follows:
The default maximum storage period for copies of files in Backup is 30 days. After expiration of the maximum storage term, Kaspersky Endpoint Security deletes the oldest files from Backup. You can cancel the time-based restriction or change the maximum file storage term.
By default, the maximum size of Backup is 100 MB. After the maximum size is reached, Kaspersky Endpoint Security automatically deletes the oldest files from Backup so that the maximum size is not exceeded. You can cancel the Backup size limit or change the maximum size.