Ok, so by now I have realised that I have committed a potentially terrible error. I deleted the Time Machine backups from my partitioned external hard drive and now I cannot delete or clear my trash. I have tried various ways including: Empty Trash. Secure Empty Trash. Option/alt key and Empty Trash. Trash it! I have also tried to erase the partition dedicated to the time machine backups, but I get an error message which says that the volume erase failed because it "couldn't unmount the disk". How should I proceed? I am in the middle of the lengthy process of of copying my data to another hard drive as I anticipate that I may have to erase the external completely. Is there any simple way of solving this problem? Ideally I just want to: a) Clear the Trash; b) make a larger partition for the time machine back up (the initial problem was that the time machine backups were too big for this partition); c) go back to my normal happy mac life. Apologies: I have looked at various threads and comments posted previously about this problem, but I am new to macs and I find them a little complicated.