According to PC Pitstop, that is not a harmful file but this is what they say:
FixCamera.exe - CameraFixer application from USB PC Camera Plus driver. Not a necessary program.
fixcamera.exe uses excessive system and memory resources with no corresponding benefit. Applications such as these should be disabled to improve overall system performance.
Since it’s not malware, there is no reason for Avast to detect it as such. It just triggers the sandbox because it performs actions that are common to things that are dangerous.