Hi, thank you for your reply. First of all I backupped the library on a different partition on another disk of my set / pc. I installed a fresh copy of SS 4.3 in Vista and then recalled the backup tool to restore the library After the four first steps the tool tried to connect with "I don't know" to authenticate the library. First tries all concluded with the connection error I posted. After some other tries the tool stayed connected (at least I could only see the window opened, but nothing I can say about it's working or not) for at least 4-5 hours and then I stopped by closing the task. my database is 7 Gb and over, so I didn't know if the tool had to pass all over to authenticate. However today I had to say some connections didn't work well (Microdoft site wasn't reachble all over the day. So I'll give another try in the future days. Can you tell me something about the duration of the authentication time? Is it depending on the amount of Gb of the Db? To which site do the connection attach? So I'll be back in a few days to report some news Thank You for all, and at last I can say I have no other chanche than using an internal device to do the backup, cause only DVD DL (and it seems to me I read Backup Tool cannot use DVD DL) can hold my entire db.