Program Not Uploading On Board

I am trying to upload my sketch on arduino, It is compiling but during the last stage of uploading it shows this error. I have tried on all my boards and I also tried re-installing the arduino ide.

Error Message--

Arduino: 1.8.8 (Windows Vista), Board: "Arduino/Genuino Uno"

Sketch uses 2574 bytes (7%) of program storage space. Maximum is 32256 bytes.
Global variables use 90 bytes (4%) of dynamic memory, leaving 1958 bytes for local variables. Maximum is 2048 bytes.
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x20
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x20
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x20
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x20
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x20
An error occurred while uploading the sketch

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Please help as i have to get back to my projects.

Do you have the correct board selected? (Arduino Uno Wifi Rev. 2 is NOT the same as Arduino Uno - lots of people seem to have gotten these for christmas and don't know this)

Do you have anything connected to pins 0, 1 or reset?

I have the same issue. Yes, I have a sensor shield board pin attached to 0 and 1 pin on the arduino board.
using Mac High Sierra OS
version 1.8.8 IDE
Board is Arduino/Genuino Uno
I'm on port dev/cu.usbmodem1411

any suggestions?