note alignment - problem solving

You can adjust individual measures with Shift-} (to expand) and shift-{ (to compress). Selecting measure 21 and using the expand allows you to line up the bar lines.

The reason they are not aligned is because MuseScore by default obeys standard typographical rules, which do no *not* call for beats to always be aligned. For instance, two eighth notes are *supposed* to take up more room than one quarter note. And four sicteenths take more room still. Whereas a half note takes less than the amount of space of two quarters. As a result of this, the spacing of beats within measures is not constant. And therefore, unless two lines are exactly identical rhythmically, it would be pure coincidence if the beats were to happen to align.

There are ways to alter how MuseScore lays things out in a way that could have the effect of making beats align better. One would be to set Style / General Style / System / Fix Measure Width. This forces all measures within a system to have the same width, and thus the larlines at least would line up. And if the barlines line up, then the beats within them will at least be closer to the same position. Also, playing the value of Style / General / Measure / Spacing might have the side effect of causing the beats within a measure to space differently, perhaps. I'm not so clear on how that value is interpreted.

Another possibility would be to make the actual time signature of the measure 1/4, and hide the etxra barlines. Then, if Fix Measure Width were set, each beat (which is a measure unto itself) would presumably end up the same width - which is ultimately what you probably want, I guess. That is, you'd presumably rather forcve beats to align by making eighths and sixteenths artifically close together (so two eighths or four sixteenths take the same space as one quarter) rather than have quarter notes within a measure not be the same distance apart.