Quote:

I have installed the latest update for 2008.5. I'm asking whether BIAB will still properly recognize a song if I manually change the extension to end in a "U".



That's easy to find out. Copy a song and rename it and try to open it. I'm sure it will work fine.

What I thought your original questions was about was HOW to do the renaming of a folder full of files. That can be done at the command prompt. For any who is interested, here's one way of doing that.

First make a copy of a folder full of files you want to rename so you can test out my commands without any risk. Keep that Windows Explorer open, so you can see the folder icon, for the next steps.

Open a command prompt by clicking the Start button > RUN. Type in CMD and press enter.

The first step in the Command prompt is to change directories to the folder you are going to rename. I use the pushd command because it works across different drives and even on network shares.
Type in the command PushD, followed by a space. Don't hit enter yet.
Now arrange your windows so you can see the folder in Windows Explorer (or on your desktop).
Drag the folder icon to the command prompt. So now the full command is pushd followed by the folder name.
Now, click in the command window and hit enter to execute the command. If the command succeeded, your command prompt will be the name of the folder full songs. (For example, it will say something like "C:\Users\Jim\Desktop\New folder>")

Now for the command to change the file extensions. Let's do it just for .SG? files first. Copy the following command and paste it in the command window by right-clicking in the command window.

for /f "tokens=*" %A in ('dir *.SG? /b') do rename "%A" "%~nA.SGU"

Press enter to execute the command.

If you have multiple songs with the same base name, the command will only rename one of them and it will give you the following message for the other files: "A duplicate file name exists, or the file cannot be found"

To rename your .MG? files, you only need to change two letters in the command:

for /f "tokens=*" %A in ('dir *.MG? /b') do rename "%A" "%~nA.MGU"