GarageBand not loading after update (10.4.11)

GarageBand no longer loads properly on my Mac after a recent update to version 10.4.11. It shows as being open on the Dock (with the white dot below the icon) and the toolbar appears at the top; but the app window itself never actually appears. It only gets as far as 'Scanning Sampler Instruments' (which makes me think that might be a cause of the issue maybe?) When I attempt to click on the toolbar to try and load a tune, the app then becomes completely unresponsive with the rainbow wheel, at which point I have to Force Quit.

Anyone else had this issue and/or know of a solution?

(I think somebody on here a while ago had a loading issue and the fault lay with plug-ins, but I've been into the same folder that was mentioned in that discussion (Library/Audio/Plug-ins/Components and nothing is in there.)