Batch conversion silently fails (and buggy MSCX conversion)

[ThePython10110]

Issue type

Import/export issue

Bug description

Attempting to run a batch convert does absolutely nothing. It must have at some point, because I have converted files in MS4 previously, but not anymore. The JSON file is formatted correctly, and there is no error code. There's no way I can find to get any kind of debug information (-d/--debug doesn't work).

Fortunately, I was generating the JSON file with a Python script, so I just skipped the JSON and made my script convert every file individually with -o. This led me to another issue: Converting to .mscx files randomly fails sometimes. Retrying the conversion (sometimes multiple times) seems to work. It's not VST related, since it happened to a score that didn't have VST's (unless the built-in reverb counts). It doesn't happen with MP3, MIDI, PDF, MXL, or MusicXML file types (I haven't tested any others). It does seem to depend on the score, since some seem to fail most of the time, and some never fail. It doesn't seem to matter which instruments the score includes (one score only had guitar, and one only had piano and strings).

Steps to reproduce

Batch convert issue

1. Create a batch convert JSON file.
2. Run <path to MuseScore4.exe> -j <path to JSON file>
3. Silently fails.

Other conversion issue

1. Try to convert a whole bunch of files
2. About a third (?) will fail to convert to .mscx

Screenshots/Screen recordings

No response

MuseScore Version

4.3.2

Regression

Yes, this used to work in a previous version of MuseScore 4.x

Operating system

OS: Windows 10 Version 2009, Arch.: x86_64

Additional context

No response