An insanely great trick to recover a cold backup database that starts needing recovery

Why would a 10g database restored from cold backup need recovery? That's messed up.

So for the second time now, we took a small (~50GB) database the other day, shut it down using "shutdown immediate", started it back up, switched logs, and then shut it down again.

We then cloned it (took a cold backup of it, and brought it up with a different name), and low-and-behold it complains that it needs recovery. WTF?

Here's the upside though: There's a way to easily recover from this and bring the database up.

Check out MetaLink Note: 175015.1 - it's somewhat cryptic, but essentially all you need to do is take the most recent REDO log and copy it to the archivelog dest location and name it to whatever archivelog name Oracle is suggesting in the recover database command, then just hit (Return) to accept the filename and begin the recovery process. Next thing you know, boom, everything is up and running.

Now to the question of why this is happening...