Playback doesn't always play back in 2.0

What do you mean by playback doesn't play? Is the cursor moving?

Which audio driver is selected in Preferences-> I/O tab?

I have the same problem

Can you be more specific? It works sometimes but not other times? What are your settings as asked of the previous reporter? Also your settings in View / Synthesizer - which soundfont? And what OS?

The error about My First Score indicates you still have old settings left over from a quite old beta / nightly build on your system. This could be wreaking all sorts of havoc on your system, including playback issues. So step one is to revert to factory settings by running from the the command line with the "-F" option or as described in https://musescore.org/en/node/35956. Reinstaling does not touch these settings; you need to follow the directions there.

What you describe with sound, though, doesn't seem likely to be directly related to this. nor does it sound like ahrdware. It sounds like an issue involving the audio utilities on your system that MuseScore uses - whatever shows in Edit / Preferences / I/O. Depending on what other programs you use, it is possible MuseScore is the only program using those particular utilities.

Anyhow, try the reset, If the problem persists, post the settings you see in Edit / Preferences / I/O.

Again, you will definitely continue to have *some* problems - including the erros about My First Score - until you do the reset as I suggested above. But whether it is connected to this paerticular problem or not I cannot say.

I know next to nothing about MacOS, sorry. But the line "Init midi driver failed" seems to indicate some part of the problem. What about the contents of Edit / Preferences / I/O?

It will do no harm to close MuseScore and complete the process in the Terminal. You don't need to keep it open. But @Marc Sabatella, when I do a factory reset I also get the line "Init midi driver failed," and I haven't had any issues with sound.

I have this issue too, but on a higher level.
I installed MS 2.0.0 6e4f74 two days ago, on a newly-setup Win7U machine. After installation, I accepted the offer of starting the software, and it worked beautifully, playing and editing scores I wrote in v1, scores I downloaded, new scores, MIDI files, etc. I was very happy with the new version.
A few hours later I started MS again, by double clicking on a score file, and there was no playback sound at all, even upon loading other files (scores or MIDIs). Tried launching it again via the Start Menu, got same result, even test writing a new score.
Repeated this many times, tried resetting Preferences to defaults, even other I/O settings, got same result. One very strange thing is that the Metronome sound always works fine, even while playing back a pre-written score or MIDI (silently). Sound from the machine itself works fine with all other software, including music players, games, system sounds, etc.
The only thing I haven't yet tried is uninstalling and reinstalling, due to time constraints. Hope to get to it soon though.
Hope to hear of some bright ideas though.

EugenioB - sounds like ypu have no soundfont. Do you see one listed in View / Synthesizer? Anything available if you press Add? If not, somehow your settings have become messed up. Try running with the "-F' option to revert to factory settings.

Marc Sabatella, thank you very much - that was indeed my problem and I have not only solved it, but also figured out the cause.
You see, I do not keep any data files at all on the system drive C. This includes the My Documents folder, which is the offered default location for all data files - I have that on a completely different drive from the system one. When I changed the settings for default file folders in Preferences, I navigated to the first one for scores, then for all the others I simply copied and pasted the root locations into the input boxes, blissfully unaware that the one for Soundfonts is a bit "special", showing multiple folders separated by semicolons. In so doing, I overwrote the default location for the included soundfont file FluidR3Mono_GM.sf3, which is located in the C:\Program Files (x86)\MuseScore 2\sound folder.
All fixed now, and the software works impressively well again :)
Thank you very much once again, and regards.

So I guess we can close this issue? Reopen if you disagree

Artie's (timborino) problem seems different and unrelated. Perhaps sonething to do with PortAudio configuration, but I know nothing about Mac audio.

I think we should leave this open to remind us that at least one system has a problem. But so far, it really does seem to be just your system, I'm afraid. Lots of people are using MuseScore 2.0 successfully on MacOS.

I can confirm I have had this problem as well, and experienced it just now using the v2.0 release.
Since I've changed back from Mac to Linux some months ago, I thought it might have been only a problem in the pre-release versions. On my old MacBook (13' Aluminum Late 2008) running MacOS X 10.9.5, I frequently could hear what you called "snap", and after that, there would be no audio output whatsoever. On my machine, pressing the increase or decrease volume keys (F11, F12) however brings back audio output (after another "snap").
I never could find reproducible steps to make it happen. It sometimes would, and sometimes not.
So I have no clue at all what could be the cause. But it definitely is not just your Mac.

Got similar problem on Win8.1. Musescore 2.0.1 64 bit. From what I have experienced this seems to be happening completely random.

Steps to reproduce is just to start musescore in however way you want. Sometimes you will here a click/pop and musescore will start to send a signal that is barely hearable, but you can see it through the sound mixer in Windows (see attached picture). Nothing else you play in musescore can be heard. I can however play all other sounds on my computer.

What kind of info does this bug need? I am here to help :)

as per that screenshot you don't have any score loaded, so what do you expect to play back?

Exactly, I don't, but Windows still recieves a signal as you can see from the mixer... The green color means it recieves and plays a signal. Strangely this signal doesn't seem to reach the speakers and I have done nothing to anything except reopening musescore. So I suspect that when reopening sometimes happen and either something is wrong with Musescore, or Windows (or drivers perhaps) does something here.

More info: the signal is hearable if I pump the volume up. It is a constant beeping tone with a constant fast tick in the background.

I am having the same problem. sound only works when I launch the app from the terminal with the line:
/Applications/MuseScore\ 2.app/Contents/MacOS/mscore -F

it has the sound font in the View->Snythsizer. when I quit it and relaunch it normally, the sound font is then gone again.

2.01 musescore
10.10.3 OSX

I've been having the same problem. I'm using MuseScore version 2.0.1 on OSX 10.9.5. Just got the software yesterday, and have found that whenever I save a project, the playback function stops working.

I've been able to "fix" the problem by reverting back to factory settings, but the next time I save, or if I open the program normally, I'm back to no sound until I exit and revert to factory settings again.

I've also noticed that when doing the factory reset, for some reason, it is unable to locate QSQLITE driver and then tries to load every single internet plug-in I have before finally arriving at Unity Web Player plugin, which it seems to like.

I also have a soundfont in View->Synthesizer, just no sound.

I am having the same problem as listed below. Mac OSX 10.8.5 musescore 2 brand new installation ie. never had it before. Been listening to a score through headphones then wanted to play it to my OH but it wouldn't work through the bluetooth even though the youtube video I was previously watching would play through Bluetooth and oddly at the same time the musescore played through my MacbookPro's external speakers. Work that out. You wouldn't think the computer would use two sound outputs at exactly the same time.

sorry duplicate posting.

Usually, what you need to do is tell MuseScore which audio device to use in the I/O section of the Preferences, then quit and reopen.

Yeah, just tried that, it didn't work. I, of course checked the connection with audio from another application which worked fine.

Can you attach a screenshot of your I/O settings?

I experience audio problems similar to Timborino. Sometimes I experience the click sounds, although it does not always preface a loss in audio, but it does now cause me to experience anxiety because of a problem I will explain last. I also find that when Musescore does not play audio, nothing will output audio. No files on my computer, internet (such as YouTube videos), or any other type of audio plays. The only way I can find to fix this is to close and restart the Musescore program an arbitrary number of times (usually number of times that I have to open and restart Musescore is < 10 but ≥ 3 or 4). In fact, I have a procedure I use to streamline the process. I will play an audio file on my desktop (using the preview function enable-able on Mac OS X, though there's no difference in playing an audio file in this way compared to any other way as far as I know) and then opening Musescore and checking if the audio is still playing out of my headphones/computer speakers; If it is, then Musescore will play audio and if not, then Musescore will not play audio. I repeat that process until I hear audio coming out of the output device (headphones/speakers). This is quicker than opening Musescore and clicking on a note written on a previous score to see if there is sound.

Now the issue that I am primarily writing about, and the issue that now causes me some anxiety when opening Musescore, is this; Rarely (incidence occurs probably about 1 in 30 times) an incredibly loud noise that I can only describe as white noise is BLASTED out of the headphones/ speakers (if I have my Macbook pro set on 1 notch up in volume using the volume buttons on the keyboard, the sound comes out as if I have my computer up 12 or 13 notches, it is definitely in a decibel range where it would cause hearing damage) and does not stop, as in it will continuously play out of the headphones/speakers, until Musescore is exited or the volume on my Macbook is brought all the way down to 0. This horrendously loud noise occurs as soon as Musescore opens. There may or may not be a correlation between this sound and the following things: Opening and closing Musescore rapidly, opening and closing Musescore rapidly with another audio source playing on my computer, having another audio source recently playing or with it paused. Additionally I recently, for the first time, experienced a similar phenomenon exactly the same in every way as the white noise phenomenon except for the following things: The sound occurred when the aforementioned procedure to get Musescore to play audio was successful (an audio file was playing while Musescore was open), the sound only started to play when I clicked on a note, and the sound was identical in volume and sound quality (it sounded as if some audio was recorded but it was severely clipping) but it was playing through the sound font (it is a sound font I bought that is a viola sound font). This problem has made me rather cautious about executing the procedure for making Musescore play audio, and I now hold the headphone out of my ear until Musescore is open to avoid the ridiculously loud white noise sound blasting me. It would be great if these things could be fixed.

Also all of these problems occur, and could potentially be reproduced, by simply opening and/or closing Musescore.

Operating system: OS X Yosemite 10.10.5
Musescore 2 Version: 2.0.2
Musescore 2 revision copied: f51dc11

It would be great to fix these problems indeed, but first we would need reliable steps to reproduce the problem on one of our own systems, and so far no one has been able to come up with such steps,

In any case, the "Assigned" field is for the programmer who will fix a problem, not the person who is reporting the problem. So unless you are a programmer volunteering to work on fixing this, please leave it unassigned :-)

After using a side palette, I can no longer get the playback to work.
With an older version, doing a factory reset seemed to solve the problem. With the new version,
I have tried uninstalling and reinstalling, but so far no success.

Did you try a factory reset with this version? This does more than uninstall / reinstall. If that doesn't fix it, please ask for help on the support forum, and include information like what OS you are on, what soundfont(s) you see lsited in View / Synthesizer, and what settings you see in Edit / Preferences / I/O.

Thanks! I have now tried the factory reset. Yes, that did work...until I used a palette again.
So, there is clearly a bug in the software.

This could be, but in order to verify that and try to fix it, we need to see the specific score that demonstrates the bug and precise steps to reproduce it, plus the relevant system information mentioned above. As far as I know know, no else seems to have any problems with palette activity interfering with playback. so it may be something unique to your system, and we'll need help figuring out what the cause is.

Well, the factory reset worked the first time I tried it.
However, now doing that doesn't work. I also tried reinstalling it, and multiple factory resets. Still no success.
I am using Windows 10.
Under View, Synthesizer is grayed out.
As for Edit / Preferences / I/O, I have tried both PortAudio and Jack Audio server, and that made no difference.

I closed MuseScore and waited a while, and then came back. The program took longer than usual to open, but it now is working. I added things from the palette, and no problems at the moment. Synthesizer is not longer grayed out. Before the items under PortAudio were blank, but now they show MME and Microsoft Sound Mapper - Output.
So, glad it is working at the moment, but it is a mystery at to why the Synthesizer grayed out, and the PortAudio settings went to blanks.

Please reopen if you can reproduce the issue with latest MuseScore 3.0 Alpha 2 or even latest nightly build.