Problems attaching a SSAS database
I found what the problem was. I had not deleted the database from its original location, after I detached it.

I copied the database to the new drive, which on my case is T:.

After I deleted the database from its original location, in my case F:\ssas\data, then I could attach the database from T:.

After attached, I checked on the  F:\ssas\data folder and SSAS had created the following structure there, see below.