Shotcut 25.03.29 / Windows 10
I tried opening a .mlt file from a network share that had only read only access, but there was no missing files dialog at startup and all the clips inside showed “INVALID”. Same file copied to a full access folder properly shows the dialog.
Slightly related: modifying the project then trying to save it while opened from this read only location results in an “There was an error saving” error, but the project thinks it is in a “saved” state (so there’s no * near title bar) and closing it doesn’t warn with the “Project has been modified, Do you want to save your changes?” thus possibly losing work without noticing.