macOS 10.5 accessibility setting “Enable Hover Text” causes crash

• Feb 10, 2021 - 20:06
Reported version
P2 - Medium
S2 - Critical

I crash every time I edit instruments. Maybe when I add the drum set to my score?


Status active needs info

In order to investigate, we would need you to attach your score and give precise steps to reproduce the problem. Also, be sure you are on the current version, 3.6, as there were some crashes in this dialog fixed not too long ago.

On macOS 11.2(.0) I don't experience problems, also not when I add a drumset to the score.
Today I will update to macOS 11.2.1 and see if that causes any problems.

Title Musescore keeps crashing with Big Sur Mac update? macOS 10.5 accessibility setting “Enable Hover Text” causes crash
Status needs info active

Hover Text was introduced in macOS 10.5 Catalina.

I was able to reproduce this bug on macOS 11.2 (e.g. pre-update to 11.2.1) with 3.6.2 and a 12 Feb 3.x Nightly:

How to reproduce

a) System Preferences -> Accessibility ->Zoom -> Enable Hover Text
b) Open MuseScore
c) Press Cmd key 3 times to lock Hover Text OR Hold in Cmd key
d) MuseScore closes/crashes when you click on it

Other applications are also experiencing issues, e.g.
Brave with Github issue on macOS 10.15 (crashes consistently)

Confirmed workaround: untick “Enable Hover Text”

Would be great if someone still on macOS 10.5.x or pre 11.2 could test and confirm if they are experiencing the same issues as confirmed reports on 11.2 and newer and adjust the title accordingly.

From Matt McClinch via MuseScore Developer Chat:
"When I build with Qt 5.9.8 and enable Hover Text, MuseScore crashes during a call to [QMacAccessibilityElement accessibilityAttributeValue:]. This does not happen when I build with Qt 5.12."

Combinations that crash

  • MuseScore 3.6.2 (and probably any older version) built on Qt 5.9.8 (either Download from or self-built) on macOS 10.15.7 (new test point), 11.2, 11.2.1.
  • MuseScore 3.x 12 February Nightly (build on Qt 5.9.8) on macOS 11.2.1

Combinations that do not crash

  • MuseScore 3.6.2 self-build on Qt 5.12 on macOS (version unknown, assumed 10.15.x or 11.x, macOS version not matter)
  • MuseScore Master (4.0) 12 February Nightly (build on Qt 5.15.x)

To summarise

  • It is safe to assume that Qt 5.9.x 8 has an incompatibility with "Hover Text",
  • Since Qt 5.9.x is EOL, this issue will not be resolved on's downloadable version.
  • Expect this issue to be resolved when MuseScore 4.0 is released.
Severity S2 - Critical S4 - Minor

Since the cause and workaround are known, I am reducing the Severity. If anyone has issues reading MuseScore GUI text, I suggest as additional workarounds:

  • increasing Font Size (from default of 13) under Preferences -> General -> Theme -> Appearance
  • and optionally maybe the GUI Scaling Factor command-line option (mscore -x 1.5)
Severity S4 - Minor S2 - Critical
Priority P2 - Medium

Crashes are always critical, workaround or not. Esp. if not just under some very rare corner cases.
Easy workaround might lower the priority

I don't specifically see where anyone mentions having tried this with earlier versions of MuseScore, but I'm kind of assuming it would probably crash for any 3.x release?

Status active fixed
Fix version 4.0.0

As there won't be any further 3.x (and even if, it'd most probably still be using Qt 5.9) and the issue is not happening with Qt 5.12 and later, and 4.0 will use Qt 5.15 (or later), let's mark this fixed in 4.0.

Fix version