I haven't done anything at all outside of the Apple ecosystem. I have a Time Machine external drive that was encrypted using the included Time Machine encryption options. I want to temporarily use this drive for something else (the contents of my computer aren't that important, I am willing to give up my backup history and take a small risk that my computer will crash in the next day or so as I go backupless). However, when I went to "Erase" the encrypted drive in Disk Utility and chose the fastest option (which doesn't even overwrite the disk), my computer told me that it was going to take 3 hours (and that was after it had already been going for a half hour, and in fact had never shown any forward progress). Normal erase procedures at the fastest option take a couple minutes. I am also normally able to simply reformat the disk as a new partition and I understand that the old data isn't overwritten, but it takes less than a minute and its all I need. In this case, the options to repartition my encrypted Time Machine drive are greyed out. How can I reformat my encrypted Time Machine drive?