I have uninstalled Ubuntu One and deleted the "Ubuntu One" directory. After reinstalling Ubuntu One all files from onlinestorage and all connected PCs were gone. is there any way to recover the files?
If you find yourself in a situation where you think Ubuntu One has removed your files you have two options. The first place to check is the computers Trash. Ubuntu One on versions of Ubuntu newer then 11.04 and all the Windows Clients move files to the computers Trash when removing them.
If that does not work there is a job that we can run in emergencies to try and recover your files. Please contact our support folks for that.
You could try to use a data recovery tool like scalpel. If the data is really important stop to use the disk NOW. Every time you write something to your disk you might delete some of the lost data permanently. . Boot from a CD and create a disk image (on a separate disk of course) and work for recovery only on this disk image. Use a tool like scalpel or foremost or something like that. Here is s good description how to use them http://ubuntumanual.org/posts/357/recover-your-deleted-files-in-ubuntu