When maximum backup collection size is exceeded the oldest back is deleted. To prevent a backup with valuable information from being deleted you should make it stationary. Stationary backups are not deleted automatically but may be deleted manually.
To make a backup stationary you should:
When backup is made stationary the Zip-file is renamed according to the following pattern:
(ProfileName)SectionName_$NNN.zip
NNN - is a 3-digit number.
Note. When making a differential backup stationary it will be first converted to normal. This ensures correct restoration of the backup.