Google-drive – My files on the Google Drive disappeared but are still searchable and use up the quota

Background: My Google account X was getting full so I tried to delete some files from the Google Drive part of the account. A and B are folders, X and Y are accounts.

I had a folder A on my Google account X that I tried to move to another Google account Y. To do this I shared the A with Y with the intention to remove A from X and store it on Y instead. I can't recall all operations I performed and in which order but approximately something like this:

• I made a new folder B on Y
• Moved all files from the (shared) folder A to B (logged in to account Y)
• Moved A, with all its content, to the Trash on account X and emptied the Trash

After doing this I realised that the files that originally were in A on X but now are in B on Y still were marked as shared, the owner of these files was set to X and that X was still full. However, I couldn't find any of the files on X using the regular file browser but I could search for them and find them.

Normally, if you look at the info panel for a file there is a field that indicates its parent:

Even when you look at an item in the root folder you can see this

But in the case with the files that originally were in A, this is how it looks when I found them through searching in account X

Where are those files?

I can search for the files on X and delete them but there were a couple of hundreds of them so it is a PITA and it's very likely that I won't find all of them/by mistake find some files that shouldn't be deleted and delete them.

I should also add that Shared with me is empty on Y.