I have used BiaB in the past, but haven't touched it in quite a while. Then my computer died. I got a new one and re-installed BiaB 2017 on the new machine. I began working to re-learn the software, and ran into an immediate problem.

I entered chords for a celtic classic, "Come To The Hills". It is in 3/4 time, so I selected an appropriate style and entered the chords for the first verse. When I play it, it counts 4 beats to the measure (not 3), and every third measure it counts a single beat and moves on to the next measure.

Is this how it is supposed to work? Am I missing something, here?

This link is to a video on YouTube showing the behavior. Any help would be appreciated.
https://youtu.be/wCh15xUCGuQ

Are you using a MIDI, SGU or MGU file you downloaded or are you using a song file you created from scratch? I noticed many of the bar numbers have the red underline that indicates the bar has custom settings, usually with the F5 Bar Settings window.

May I suggest you save a backup copy of your song file by saving it under a new name. Then right click in the chord area of any bar and press F5 on your computer keyboard to open the F5 Bar Settings window. Select "reset all bars" to remove all the F5 bar settings.

Regenerate the tracks and playback the song. Does resetting the F5 bar settings make a difference?

Jim is likely on to something with the F5 settings. Otherwise, welcome to the forum, the video was a nice touch for a newbee.

Think about uploading the BIAB file which would allow us to see what is behind the curtain, if you need to.

Welcome to the forums also. Great video and clear explanation.
In the F5 bar settings, before doing the reset, you can select Print Summary, which might then show you exactly what is creating your issue.

The project was created from scratch, with File --> New. I don't know why every measure showed the red line...I just entered the chords manually.

Following the advice here, I hit F5 and reset all bars. Surprisingly, every measure still had 4 beats. So I went in to measure 1, hit F5, and set the beats per measure to 3. That fixed it. Not sure why that was necessary, but it plays correctly, now.

I decided to create the song a second time from scratch and see what happened, and it worked fine. So I don't know what happened with the first one, but at least I now know how to handle it if something similar happens in the future.

Thanks for the advice, all.

Glad you got it worked out. Welcome back to Band-in-a-Box and welcome to the forum!