The fewer issues I have to read, the more new features I will have time to implement, so I ask that you please try these things first
Description
The current message isn't very descriptive (where did I run out of space?) and sounds somewhat accusatory.
I would suggest adding the output location to the message; also rephrasing it as something like "The output location has no disk space remaining" could sound more neutral.
Thanks!
Edit to add: I just noticed I got an "unhandled error" popup that somehow opened in another window behind my main LosslessCut window (I'm using the latest AppImage, version 3.67.2); this popup had "no space left on device" followed by a traceback; I would assume this pop-up isn't meant to be the primary user-facing message.