Been using Ardour for a while now. Can’t say I’ve experienced this problem before.
I created a new project. I added a pre-recorded track to the project.
I added a FluidSynth MIDI track to the project, and loaded up an SF2 set of drum samples I have and add some MIDI drums. Everything is working fine. I save the project and close Ardour.
After returning to Ardour, I open the project again, and none of my drums make a sound.
I open up the FluidSynth and my SF2 is not loaded.
I attempt to reload the SF2 and show’s as loaded by the Channels are empty.
I remember having had issues when I messed around with the directory path names. Quick fix for me was to correct the file names in the related .ttl files somewhere down plugins/…
I use a workaround: load a SF2 file, then save it as a preset (named like the file) in the plugin. This way, if the file connection get lost, at least I don’t have the hassle to get through all the folder structure over an over again. I just choose the preset.