Contents

• No sound
• My MIDI device has gone quiet
• A note is stuck or ringing
• A file will not load
• A file sounds wrong on my synth
• The bass plays as drums, or everything sounds like a piano
• Cover art is not showing
• Lyrics are blank
• The interface is too big or too small
• I want to start fresh
• The app will not open on first launch
• Older hardware and macOS drivers
• Reporting a crash or bug
• Related pages

Help & Troubleshooting

Something not behaving, or just stuck on something? This is the page for help. Most hiccups have a quick fix, and the common ones are gathered below. Work down the relevant section and you will usually be back up and running in a minute or two.

After a quick answer rather than a fix? The FAQ covers the questions that come up most, each pointing at the page that goes into detail.

If you cannot find the answer here, the Reporting a crash or bug section near the bottom has the contact form and how to send a useful report.

No sound#

Silence is almost always a routing or volume issue rather than anything broken. Run through these in order.

1. Check your output in Settings → MIDI Output (⌘,). Make sure a device or the built-in synth is selected and marked Active. See MIDI Output & Devices.
2. Check the hardware: is your synth or interface connected and powered on? Try it with another app to confirm it works.
3. Try the built-in synth: switch to Built-in Software Synth to rule out a hardware issue.
4. Check the volume: make sure the transport volume (and the Mixer) is not at zero, and that channels are not muted.

My MIDI device has gone quiet#

Different from having no sound at all: everything was playing happily, then the music stopped reaching your device. The track carries on, the display keeps moving, but the synth sits silent. This most often happens after switching a device off and on again while PXR is running, or after knocking its USB cable.

The cause is usually outside PXR. When a device disappears and comes back, macOS can leave the connection looking perfectly healthy when it is not, and PXR is told its notes were delivered even though nothing arrives. That is why the app cannot always spot it for you, though it does tell you whenever your Mac admits the device is unreachable.

Work down these in order. The first two fix it most of the time.

1. Rescan your devices: choose MIDI → Rescan MIDI Devices. In Settings → MIDI Output the same thing sits on the Reconnect button, which appears with a warning naming the device whenever PXR knows it has gone offline. Either one looks for your devices again and reconnects, including when your Mac has quietly given the device a new identity.

2. Switch the device off and on again, or unplug and replug its cable, then rescan as above. Give it a few seconds to reappear.

3. Check the device list in Settings → MIDI Output. A device marked Offline is one your Mac cannot currently reach, which points at the cable, the power, or the driver rather than at PXR. If your device is missing from the list altogether, it is not reaching your Mac at all.

4. Try another app to confirm whether your Mac can reach the device at all. If nothing can, it is a system or driver matter, not a PXR one.

5. Quit and reopen PXR, which rebuilds its connections from scratch.

6. Restart your Mac's MIDI system. If a device stays stubbornly silent everywhere despite being on and connected, macOS itself may be holding a dead connection. Open Terminal and run:

   killall MIDIServer
   

   Nothing is lost and no restart is needed: your Mac starts it again by itself the moment an app next asks for MIDI. Reopen PXR afterwards.

Older gear is the usual candidate here, and its driver is usually the reason. See Older hardware and macOS drivers below, particularly if you are using a Roland SC-8850 over USB.

A note is stuck or ringing#

It happens, and it is easily cured. Use MIDI → MIDI Panic (⌘⇧.) to silence every note and reset controllers. Stopping playback or clearing the playlist also silences hanging notes.

A file will not load#

If a file refuses to open, the format is the usual culprit.

• Make sure it is a valid Standard MIDI File with a .mid, .midi, or .kar extension. PXR supports Type 0 and Type 1 files.
• A corrupt or non-standard file may fail to open; try another file to confirm PXR is working.

A file sounds wrong on my synth#

If the music plays but the instruments are off, the file and your device probably disagree about which sound standard is in use. A few things to try:

• The file may be written for a different sound standard than your device expects. Try the right format routing, or the playback options like Force SC-55 Instrument Map in Settings → Playback.
• On Yamaha MU hardware, an older (MU80-era) file can sound wrong on a newer module. Try XG Basic mode (⌃B). See XG compatibility modes.
• Send the matching reset from the MIDI menu (GM, GS, XG, or MT-32) before playing.
• Open the SysEx Console to see what setup messages the file is sending.

The bass plays as drums, or everything sounds like a piano#

Two symptoms that arrive together, usually on a file from the late 1980s or very early 1990s. The bass line comes out as a clatter of drums, the real drum part plays as some tuned instrument, and every other part sounds like the same piano.

The file predates General MIDI, or simply ignores it. GM fixed two conventions that make a file portable: drums live on channel 10, and a file says which instrument each channel should use. Sequences written before that were made for one particular set of hardware sitting in one particular studio. The sounds were already chosen on the front panels of the instruments, so the file never needed to ask for them, and the drum machine answered on whichever channel it happened to be set to.

Play such a file on any General MIDI device and two things go wrong at once. Whatever sits on channel 10 is heard as drums, which is why a bass line turns percussive. And with no instrument requests in the file, every channel falls back to the default piano.

This is not specific to PXR. Any player or synth that follows General MIDI behaves the same way, because there is nothing inside the file to work from. It does not say which machine it was written for, so nothing can put it right automatically. It is the same difficulty that makes MT-32 files play with the wrong instruments, except that MT-32 music is common enough to be worth a dedicated mode, which PXR has. A one-off studio layout cannot be guessed.

Confirming it. Open File → File Info (⌘I) and look at three things:

• Channels Used. An unusual spread, with channel 14 or 16 in use and nothing sensible on 10, is a strong hint.
• Drum Channels. This reports what General MIDI says, which is channel 10. If the part you hear there is clearly not a kit, the file disagrees with GM.
• Track Names. Old sequences often name the hardware outright, for example "Drums - HR-16", which was an Alesis drum machine. That tells you what the file was written for.

Putting it right means editing the file, in any MIDI editor that can move events between channels:

1. Move the drum part onto channel 10. If channel 10 already holds something, as it usually does, swap the two channels rather than moving one on top of the other.
2. Add an instrument change at the start of each channel, so the parts stop defaulting to piano.
3. Send a GM reset from the MIDI menu before playing, so nothing is left over from the previous file.

The drum notes themselves are often already fine, because the note numbers for kick, snare, hi-hat and cymbals settled into their familiar places before GM wrote them down. In that case the kit only needs moving to channel 10, not renumbering.

Cover art is not showing#

PXR looks for artwork right next to the music, so a missing image usually comes down to where the file lives or what it is called.

• The image must sit in the same folder as the MIDI file, named cover.jpg / cover.png (or after the file's Content ID). See File Info & Cover Art.
• Add the folder under Settings → General → MIDI Library Folders so PXR can read it.
• Use Cover Art Recheck in File Info to rescan.

Lyrics are blank#

Nothing is broken here. The lyrics window only has something to show if the file actually contains embedded words, and plenty of MIDI files simply do not. Check the file's contents in File Info.

The interface is too big or too small#

Whatever your screen, you can scale PXR to suit. Adjust Window Size in Settings → Display, or use Zoom In / Out / Reset (⌘+, ⌘-, ⌘0).

I want to start fresh#

If you have changed a lot and want a clean slate, you can wipe the slate in one go. Settings → Support → Reset to Defaults returns every setting to its factory state.

The app will not open on first launch#

From version 1.2.6 onwards, PXR MIDI Player is signed with an Apple Developer ID and notarised by Apple, so it should simply open. Two things can still get in the way.

You are opening a download from before 1.2.6. Those versions are not signed, so they show a warning about an unidentified developer, or say the app "could not be verified". Downloading the current version is the easy answer. To open the copy you already have instead, see Installing & First Launch, which covers both macOS 14 and macOS 15 and later, since Apple changed the method between them.

You were offline on the very first launch. Apple's check runs online the first time a newly downloaded app opens. With no connection at all, that check can stall or fail. Connect to the internet and open the app again, and it will settle. The result is remembered, so it only ever applies to the first run.

Older hardware and macOS drivers#

Vintage gear and modern macOS do not always see eye to eye, usually because of ageing drivers. The common cases have known fixes, though.

• Roland SC-8850 (USB): Roland's original USB driver relied on kernel extensions that Apple removed in macOS 11 and later, so it does not work on modern macOS. A free, open-source CoreMIDI plug-in called MultiRolandDriver restores support. The SC-8850's serial and MIDI connections are unaffected.
  • Project page: github.com/lnswlrd/MultiRolandDriver
  • SC-8850 compatibility notes: MultiRolandDriver issue #3
  • Switching the unit off and on again with the cable still connected can leave it silent until the connection is rebuilt. See My MIDI device has gone quiet.
• Yamaha USB MIDI: Yamaha provides an actively maintained USB MIDI driver for macOS that works on current versions, so MU-series modules connect without trouble.

Reporting a crash or bug#

If PXR closes unexpectedly, the next time you launch it the app can offer to send the crash report so the problem can be looked into. Sending it is always your choice, and it genuinely helps make the app better.

For anything else, or if you simply have a question, get in touch via the contact form at pixelrefresh.com/contact. The single most helpful thing to include is a saved PXR Log (⌘5); for a timecode sync issue, turn on its MTC Diagnostics option first.

One honest word: because PXR is a free project built in spare time, there is no promise of a response time or a guaranteed fix for every issue. Your feedback is always welcome though, and it genuinely helps shape future updates.

Related pages#

• MIDI Output & Devices
• Settings Reference