why error in arduino but in atmega8 proteus does not matter

wiring.c.o (symbol from plugin): In function __vector_9': (.text+0x0): multiple definition of __vector_9' C:\Users\syste\AppData\Local\Temp\arduino\sketches\6F366EA3D470A87D93EB4DC2BC21772D\sketch\87segmentupdown.ino.cpp.o (symbol from plugin):(.text+0x0): first defined here collect2.exe: error: ld returned 1 exit status

exit status 1

Compilation error: exit status 1

Please help me, I hope it can be resolved quickly heheh