I have not used the application in a long time, and I realised the collection was gone.
I tried uninstalling and updating to no avail, then I found out that the original drive letter was renamed. This happened when I cleaned the computer case and updated windows.
I renamed the same drive to the previous letter, and the application was fixed and all the collections re-appeared after moving the vghd folder from the back ups I had made (You can re-download if you do not have back ups).
I hope this helps someone!
Ciao!