Backup THE SD CARD (%USERPROFILE%\.Virtualbox\HardDisks\youwave_vm01.vdi) and you won't lose anything.
1) Copy the file mentioned before.
2) Paste it in your documents folder, I don't know... wherever you can find it later.
3) Uninstall YouWave.
4) Install it again.
5) Copy youwave_vm01.vdi and paste it into %USERPROFILE%\.Virtualbox\HardDisks\.
6) Replace the existing file.
7) Start YouWave.