If you are trying to upload a sketch to your Arduino board and encounter this error message, it means that there is a communication problem between your computer and the Arduino. This can be caused by various factors, such as:

• Incorrect board selection or port configuration in the Arduino IDE
• Faulty USB cable or port
• Interference from other devices connected to the Arduino pins
• Damaged bootloader or microcontroller on the Arduino board

To troubleshoot this issue, you can follow these steps:

Step 1: Check the Board and Port Settings

Make sure you have selected the correct board type and processor variant in the Tools > Board menu of the Arduino IDE. For example, if you are using an Arduino Uno, select “Arduino Uno” and “ATmega328P“.

Next, make sure you have selected the correct serial port in the Tools > Port menu of the Arduino IDE. The port name should match the one that appears when you plug in your Arduino board to your computer. For example, on Windows, it might look like “COM3 (Arduino Uno)”.

If you are not sure which port is your Arduino, you can try disconnecting and reconnecting your USB cable and see which port appears or disappears in the menu.

Step 2: Check the USB Cable and Port

Sometimes, the USB cable or port can be faulty or loose, causing intermittent or no connection between your computer and the Arduino. To rule out this possibility, try using a different USB cable or port and see if the error goes away. You can also try using a powered USB hub to provide more stable power to your Arduino board.

Step 3: Check the Arduino Pins

Some devices or shields connected to the Arduino pins can interfere with the serial communication between your computer and the Arduino. This is especially true for pins 0 and 1, which are used for serial communication by default. To rule out this possibility, try disconnecting any devices or shields from your Arduino pins and see if the error goes away. You can also try uploading a blank sketch (with nothing in setup() or loop()) to clear any previous code that might be using the pins.

Step 4: Check the Bootloader and Microcontroller

If none of the above steps solve the issue, it is possible that your Arduino bootloader or microcontroller is damaged or corrupted. The bootloader is a small program that runs on your Arduino board and allows it to communicate with your computer and upload sketches. The microcontroller is the main chip that executes your sketches on your Arduino board.

To check if your bootloader or microcontroller is working properly, you can try using another Arduino board as an ISP (In-System Programmer) to reflash the bootloader or upload sketches directly to your problematic board. You can follow this tutorial on how to do this.

Alternatively, you can try replacing the microcontroller chip on your board with a new one, if it is removable (such as on an Arduino Uno). You can buy a new chip with a preloaded bootloader from various online sources.

Conclusion

I hope this blog post has helped you solve the issue “avrdude: stk500_getsync(): not in sync: resp=0x00” when uploading sketches to your Arduino board. If you have any questions or feedback, please leave a comment below.

So the reader is aware: This article covers the main causes for this issue, but some of the other Instructable users have found somewhat "niche" causes to the issue that were not covered in this article and are discussed in the comment section below. If this article does not solve your problem, please visit the comment section below.

I have had this error: I would plug my Arduino Uno into my Windows 7 PC (this guide should be relevant for Windows 8, Vista and XP also) but whenever I would upload any sketch to the board, all I would get is

avrdude stk500_getsync() not in sync resp=0x30

for a response. This board however worked seamlessly with my Linux machine.

After much searching online, I found there was no 'clear' solution to this.

Joyfully, the fix is actually very easy (at least for me, hopefully for you as well!). So far, there seems to be

2

3 big causes to this issue:

• A wire is connected to pin0
• You have the wrong COM port selected (the IDE does not see your board)
• Your Arduino drivers are not set properly.

Unlikely Cause

1: Bootloader is missing

Before we begin, we should check the bootloader of the Arduino for comprehension. If the bootloader is gone or corrupt, this can cause the issue.

To do this: power and reset the board. Check to see if the pin 13 built-in LED lights; if it is not then your bootloader may be missing. If this is the case, then your problem is beyond the scope of this guide. I would suggest visiting this Sparkfun guide: http://www.sparkfun.com/tutorials/247.

If the LED lights, then your bootloader still exists.

Cause

0: Wire coming out of pin 0, (RX)

All credit goes to tvance929 and his comment below for finding this one. Some people seem to have this happen to them so it seems worth it to bring this up top here.

Apparently this issue will also occur if you have a wire connected to pin 0 (RX) on the Arduino.

Cause

1: Wrong COM Port or Wrong Arduino Board selected

With the Arduino plugged to the computer, open "Device Manager" and check the "Ports". Check to see if an Arduino device is listed here; if it is, then make note of which COM port the Arduino is on and check that you have this selected in the Arduino IDE (Tools -> Serial Ports). If the COM port your board is on does not show within the IDE, then try different USB ports.

If you can't even see "Ports"; then for some reason, your computer isn't even recognizing that a device is plugged into it. Test your computer by plugging other USB devices into that port. Possibly your Arduino fails at life; try it with other computers.

It appears some have received this issue by having the incorrect Arduino board selected as cdogjune has pointed out. Check that you have picked the right board in the "Tools" menu.

Cause

2: Drivers not Installed

This is what you should see when you open Device Manager:

If you don't see an Arduino device listed under Ports; then you are probably seeing an "Unknown Device". Check to make sure that "Unknown Device" is indeed, the Arduino by plugging and unplugging the board from the computer. "Unknown Device" should appear and reappear. Assuming this is the case, you will need to install the drivers manually for your Arduino. Windows XP, Vista and 7 users may continue with the guide; if you are a Windows8 user, then please make reference to the comment left by finnigan16 below.

Right click on that "Unknown Device" and select "Properties". Click on the "Driver" Tab. Below, you can see I already have the driver set, hence why my window reads "Arduino UNO R3 (COM4) Properties", when yours will probably read "Unknown Device Properties".

Select to "Update Driver..." and then choose to select the folder containing the driver on your computer. Conveniently, you already have the drivers for the Arduino on your computer when you downloaded the Arduino IDE. Navigate to the Arduino folder you downloaded that contains the Arduino IDE. In that folder, go to the "drivers" folder and choose the "drivers" folder itself (see the picture below for the path). The computer should automatically choose to install one of the drivers within the folder you selected. Simply proceed with the installation and that should fix the problem.

Make sure the Serial Port is then selected correctly!

If you have checked the possible causes discussed here and your issue still isn't solved, be sure to check the comment section. Some of you have found niche causes to the issues which are discussed below.