EFB was installed on the volume E:. I do not know why, but after uninstalling EFB, having erased its registry key and reinstalled (EFB) on C: now it works ... Thanks, regards.
After months of satisfactory use this morning the display unit refused to start with the following error: "An unhandled exception ('System.ArgumentOutOfRangeException') occurred in AivlaSoft.Efb.DisplayUnit.exe [5288]. Any idea?