Version 3.0 one month later
One month ago version 3 was released over my objections. My biggest concern was that people would see it and abandon MuseScore forever due to many bugs and shortcomings. A few people have said they would do this, thankfully more have said they would wait for version 3 to get better. There is actually an upside to officially releasing version 3, a lot of people have found bugs we didn't know previously existed because they were not reported during prerelease testing. In this open source environment, the users properly reporting bugs and making suggestions are extremely important.
Version 3.0.2 is on the verge of being released, my best guess is 1 to 2 weeks from now, though Anatoly doesn't even have a date set yet. There will be improvements, but there are still a large number of major bugs that need to be fixed. This list is actually targeted at 3.0.3, but anything that can be fixed in 3.0.2 would be welcomed.
MuseScore 3 won't start. See #280776: Musescore 3 won't open for example. I realize this bug will be difficult to fix since the programmers cannot reproduce it. Those of us who help others on the forum need to be more proactive in trying to chase down the cause of this rather than simply marking the item as Needs info. We need to know about these systems so this bug that should be (but can't be) identified as a Blocker can be fixed.
Translations don't update. This should be identified as a Blocker. In the international community of MuseScore this should be a priority. See #280001: Updating translations fails for some languages (but works for others) for example.
Many windows are too big. The pat answer is for the user to change the system setup so MuseScore will look right. The correct answer is that MuseScore needs to do a better job of managing window sizes like it did in version 2. Due to the poor search capabilities on MuseScore.org I can't find the recent discussions of this in the past couple of weeks. I keep finding discussions from years ago in a random order.
Spurious clefs and key signatures. #280390: Spurious key change after transposition is but one example. Unnecessary Clef and key changes make the program totally unusable for anyone trying to do a professional notation project. This isn't a good thing for a Notation program.
Cross staff notation issues. There are several issues related to beams disappearing, slurs refusing to cooperate and so forth. See #279182: Cross-staff slurs/ties trying to avoid note on wrong staff and #280969: Cross staff 8ths lose beam if all notes moved to staff above . Piano music seems to be the most common music on MuseScore.
Beaming issues. There are several beaming issues leading to crashes including #282352: Beaming 8th notes across barline and creating text causes crash and #280108: Copying voice 2 notes with beams causes crash
Playback of the entire score when viewing a part. This is probably the most common complaint I've seen. There needs to be an easier way to switch between the two play methods in a part. See #109941: Regression—playback in single part instead plays full score, which was identified as a problem almost 3 years before release.
The album feature. It doesn't work but needs to. There is talk about fixing this, but I'm not aware of work being done to fix it.
I know that there are things being actively worked on like broken Plugins, so I haven't included those even though they are required to work for MuseScore 3 to be a usable program.
One final thing that needs to be fixed, and I've see a little discussion but no solutions. The program gets so slow when your working on a score with several instruments way too fast. Having to break down all scores into groups of less than 150 measures to prevent it from being unusable is not acceptable. One of the features of MuseScore 3 bragged about a year ago is that it was supposed to be faster. This didn't happen. A fixed album feature would be an improvement, but not a solution.
Related to this is the broken Save selection feature. I recommend that no one use this because it will fail unless the entire score is in 4/4. In version 2 you could use this to start a new score from an existing one.
So, what can the average user do? Keep issues that prevent you from being able to write music at the top of the minds of the programmers, either by commenting in the forums or making sure the issues in the tracker don't go months without being commented on. Make sure you report bugs and answer the programmers questions, otherwise they are very unlikely to be fixed.