First crash, debug mode (-D all), JACK backend (PW-jack): gui: valid request, calling ::do_request() PBD::DEBUG::AbstractUI: PBD::DEBUG::AbstractUI: gui: allocated normal heap request of type 1, caller butler PBD::DEBUG::AbstractUI: gui/butler queue call-slot using functor @ 0x7f28dc0efd40, invalidation 0 PBD::DEBUG::AbstractUI: gui reading requests from RB[11] @ 0x7f28f80027a0 for thread 139814024242880, requests = 21 + 0 PBD::DEBUG::AbstractUI: gui/butler/139813467395776 send heap request type 1 IR 0 gui: valid request, unlocking before calling PBD::DEBUG::AbstractUI: gui: valid request, calling ::do_request() DEBUG::EventLoop: gui: signal_new_request ardour-7.4.220: ../libs/ardour/session.cc:4669: void ARDOUR::Session::remove_source(std::weak_ptr, bool): Assertion `!source->used ()' failed. PBD::DEBUG::AbstractUI: gui reading requests from RB[11] @ 0x7f28f80027a0 for thread 139814024242880, requests = 20 + 0 PBD::DEBUG::AbstractUI: gui: valid request, unlocking before calling PBD::DEBUG::AbstractUI: gui: valid request, calling ::do_request() PBD::DEBUG::AbstractUI: gui reading requests from RB[11] @ 0x7f28f80027a0 for thread 139814024242880, requests = 19 + 0 PBD::DEBUG::AbstractUI: gui: valid request, unlocking before calling Segmentation fault (core dumped) Second crash, debug mode (-D all), JACK backend (PW-jack): PBD::DEBUG::AbstractUI: gui reading requests from RB[11] @ 0x7fd464000e30 for thread 140549784860352, requests = 40 + 0 PBD::DEBUG::AbstractUI: gui: valid request, unlocking before calling PBD::DEBUG::AbstractUI: gui: valid request, calling ::do_request() PBD::DEBUG::AbstractUI: gui reading requests from RB[11] @ 0x7fd464000e30 for thread 140549784860352, requests = 39 + 0 PBD::DEBUG::AbstractUI: gui: valid request, unlocking before calling PBD::DEBUG::AbstractUI: gui: valid request, calling ::do_request() PBD::DEBUG::AbstractUI: gui: allocated normal heap request of type 1, caller butler PBD::DEBUG::AbstractUI: gui/butler queue call-slot using functor @ 0x7fd44809ad40, invalidation 0 PBD::DEBUG::AbstractUI: PBD::DEBUG::AbstractUI: gui/butler/140549718394560 send heap request type 1 IR 0 gui reading requests from RB[11] @ 0x7fd464000e30 for thread 140549784860352, requests = 38 + 0 PBD::DEBUG::AbstractUI: gui: valid request, unlocking before calling PBD::DEBUG::AbstractUI: gui: valid request, calling ::do_request() DEBUG::EventLoop: gui: signal_new_request PBD::DEBUG::AbstractUI: gui: allocated normal heap request of type 1, caller butler PBD::DEBUG::AbstractUI: gui/butler queue call-slot using functor @ 0x7fd44809ad40, invalidation 0 PBD::DEBUG::AbstractUI: PBD::DEBUG::AbstractUI: gui/butler/140549718394560 send heap request type 1 IR 0 gui reading requests from RB[11] @ 0x7fd464000e30 for thread 140549784860352, requests = 37 + 0 PBD::DEBUG::AbstractUI: gui: valid request, unlocking before calling PBD::DEBUG::AbstractUI: gui: valid request, calling ::do_request() DEBUG::EventLoop: gui: signal_new_request ardour-7.4.220: ../libs/ardour/session.cc:4669: void ARDOUR::Session::remove_source(std::weak_ptr, bool): Assertion `!source->used ()' failed. Aborted (core dumped) Third crash, normal mode - unable to run in debug mode and switch audio backend, Ardour crashes every time. ALSA backend: AlsaSeqMidiIO: cannot connect output port. AlsaSeqMidiIO: cannot connect input port. AlsaSeqMidiIO: cannot connect output port. AlsaSeqMidiIO: cannot connect input port. Cue Control in new MIDI buffer of size 8192 MIDI Clock in new MIDI buffer of size 8192 MIDI Clock out new MIDI buffer of size 8192 MMC in new MIDI buffer of size 8192 MMC out new MIDI buffer of size 8192 MTC in new MIDI buffer of size 8192 MTC out new MIDI buffer of size 8192 Scene in new MIDI buffer of size 8192 Scene out new MIDI buffer of size 8192 x-virtual-keyboard new MIDI buffer of size 8192 AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending AudioSource destroyed with leftover peak data pending Bad use dec for Take277_Audio 1-1.wav Bad use dec for Take277_Audio 1-1.wav Aborted (core dumped)