I spend most of my time in Linux, inside VMWare, but I do use Windows for a few things like music. (VMWare's sound drivers are a little unstable.) I use Windows Media Player, since I'm lazy and it comes with Windows.

Recently I had to switch Windows users on my computer. To get back all my stuff, I had to copy all of the files in C:\Documents and Settings\olduser to C:\Documents and Settings\newuser.

This worked surprisingly well, except for my playlists. When I started WMP, and when I tried to play any playlist, it complained:

Windows Media Player encountered an unknown error. This can occur when another program or operating system component encounters a problem but does not communicate the nature of the problem to the Player.

I first realized that a number of playlists (.wpl files) were in C:\Documents and Settings\All Users\Shared Documents\Shared Music\My Playlists, so I copied those into C:\Documents and Settings\newuser\My Documents\My Music\My Playlists.

Second, I looked inside the playlist files themselves. A number of them had olduser's playlist directory hard-coded. So, I changed every line like this:

<media src="C:\Documents and Settings\olduser...

to this:

<media src="C:\Documents and Settings\newuser...

(There were a lot. Thank god for emacs search-and-replace in dired-mode.)

Now, when I ran WMP, it showed multiple copies of each playlist, but it still complained and wouldn't play them.

After some more head-scratching, I realized that it was caching the playlists in its database. I went into C:\Documents and Settings\newuser\Local Settings\Application Data\Microsoft\Media Player and deleted *.wmdb. When I restarted WMP, it rebuilt the database from scratch and it was happy again.

Moral of the story? Don't change Windows users if you can possibly help it. It's really painful.

See also:

• fedora core 3 on vmware
• invert mouse in Beyond Good & Evil