Library backup and impossible restore

Are you restoring to the same version from which you backed-up?

Hi Pulse, yes
i restore my pc from restoring partition D

 is  reinstalled everything as before from HP

sorry for my english

@Jonny > When you did your backup, did you also backup the music collection or just the database?

Hi Pulse, yes also music collection

Is the user name (and path to the user directory) the exact same as it was before?

Pulse I not changed nothing about default folder where rekordbox put files

not remember about user name (bot not i'm sure that i have understood what you mean)

@Jonny > When you create a user profile on any computer, it creates a user account folder. If you have restored your data, it may be in the correct location but the database may all point to a different source folder, thus giving the indication to the program you're not on the same computer as before.

Under Windows 8 you should be able to find your username by going to C:\Windows\Users -- the folders there will have your username. I'm not sure if you'll have access to the previous rekordbox settings file to determine if they match or not, but you may recall whether or not the user names match just by looking.

Just as an FYI: You can still restore the database, even if it gives the warning. That message is just to advise you that it was backed-up on another computer, but you can still proceed with the restoration.