Symptoms
While accessing the Backup Manager at Tools & Settings > Backup Manager:
PLESK_WARN: Warning: Some of the files in the FTP storage are not shown in the list because the names of those files do not conform to the naming convention of backup files. If you are sure that those files are valid backups, rename them to match the following pattern: “backup_<YYMMDDHHmm>.tar”
PLESK_WARN: Warning: Some of the files in the storage Amazon S3 Backup are not shown in the list because the names of those files do not conform to the naming convention of backup files. If you are sure that those files are valid backups, rename them to match the following pattern: “backup_<YYMMDDHHmm>.tar”
Cause
Files not related to Plesk backup are stored on remote backup storage (FTP, Amazon S3, etc) in the same folder as Plesk backups.
Resolution
Remove or move files not related to Plesk backup from the remote backup storage folder.