I reinstalled windows on the laptop of my daughter. Before doing this we made a copy of her music, pictures and so on on an external drive which was formatted in NTFS. Unfortunately, the folder we created for the backup was empty (I checked after I reinstalled windows). Today a miracle happened, as suddenly the data were back but when I tried to copy them to another place they disappeared again. Checking the external drive with disk utility I got the message "filesystem is not clean". Is there a way to recover the data? Preferred solution would be a tool with a gui. The drive I need to repair is formatted in NTFS and is connected via usb to laptop.
If it is a linux partition (ext4)
Go into a LiveCD or LiveUSB, then run
If it is a Windows or NTFS partition
If the drive is "NTFS" and its returning unclean, you should boot into Windows and run a chkdisk on that partition. Within Linux, if you run an fsck on NTFS, its likely to break something (NTFS is a windows format, so you should use windows chkdisk). The NTFS fsck, while it may find the general errors, may cause problems if you need to run the NTFS drive within Windows.
Windows specific advice:
PLEASE READ CAREFULLY.
If you formatted your drive as described, during a (re-)install of Windows, then Linux is not your first priority.
You need an Unerase utility (for NTFS), and you need to use it before attempting to use chkdsk or any other tool.
Ubuntu forum advice:
Ubuntu (and other Linux variants) are quite capable of reading NTFS (and older) Windows-based file systems. This is a good method of data recovery when the OS has become unusable, too slow, or infected with malware.
However, this is no panacea. If you are confronted with driver format errors or corrupted data, then a Windows-specific tools (used correctly) is you best solution.
Just read your 'minor update'. This is confusing, as your original description of re-installing Windows (and overwriting data) is inconsistent with this being an external drive in NTFS format.
Are you trying to recover the backup data (from this external drive), or the drive where you re-installed Windows (overwriting the original data)?