a6bb6589_seUS_Todo_Backup__online_help___Meaning
[Error Codes] 0X*****257 [Error Codes_2] 0X*****447 [Meaning_3] Failed to recover part of database. [Meaning] 
The 26 drive letters have been taken,please release one to continue.
Error Code list of EaseUS Todo Backup- online help.
Meaning