Event ID 58059: "Media is unrecognized. The media in drive '<drive>' is written in an unrecognized format. Erase the media to make it usable" is reported in the Event Viewer Application Log.
Event ID: 58059
Source: Backup Exec
Description: Backup Exec Alert: Media Information
(Server: "ServerName") (Job: "JobName") Media is unrecognized.
The media in drive '<Drive>' is written in an unrecognized format. Erase the media to make it usable.
Backup Exec is attempting to overwrite media and the media was previously written to in a tape format that Backup Exec does not understand. In order for Backup Exec to write to this media, the media must be erased.
For instructions on erasing a media, refer to the Related Articles section on the right hand side facet of this article.