When I listened to the DEMO of each music style, I found that some were very fast and some were very slow.
I found that the ones that are very slow, the playback address is the URL. If you are on the other side of the world, due to network reasons, sometimes the playback is very slow or even impossible to play.

I don't understand why BIAB puts the music style DEMO on the website. Is it because of copyright?
Can it be designed to allow customers to choose whether to play locally or online.

Some are slow, some are fast.
This will cause customers to feel uncomfortable when listening to music style demos, with lags, stops, and no sound occurring.

Which demos are you talking about? If the demo exists locally, Band-in-a-Box SHOULD play that one (instead of the online one)

Many music styles are played online as demos

_CLASSIC.sty. Classic Vintage Country Swing

_UNDERGO.sty. Undergo Praise Power Ballad

_HARRIS.STY. Harris Modern Country Rock

Obviously, not all Demo songs are available locally, and if a local file is not found, as Andrew explained, BiaB automatically plays the version hosted on their web site.

I'm not sure how this relates to the comments:

The tempo of the song demo has nothing to do with the location they are stored at. The suggested tempo is always found in the Style Picker column:

What I mean by fast and slow is that the song demo plays slowly on the website.
I have never said whether the song BPM is fast or slow.

I hope the song demo is on the local hard disk, so that you can double-click immediately to hear, I do not know whether it is possible.

OK, I follow better. This sounds as though it is related to your Internet speed, and not to the issue with the online demo songs.

if you run this test from the following link, what value does it give you for download and upload speeds?

https://www.whatismyip.com/internet-speed-test/

You can download any missing wma style demos to X:\bb\RealTracks\Data\Style Demos Audio
_SPATE.sty = https://demos.pgmusic.com/audio/allstyledemos2/_SPATE.wma

According to your prompts, I downloaded successfully, and then I put it in the directory you mentioned.

But when I click on the music style, it still plays through the network.

thanks to musocity!

Problem solving. You are a genius.