Must Reboot Laptop Prior to Uploading Sketch

After uploading the first sketch or two, the Arduino will no longer accept uploads and gives the error message: "avrdude: stk500_getsync(): not in sync: resp=0x00". The only way I've figured out how to get it working again is to reboot the laptop. This, of course, is very annoying and makes the system virtually unusable. I've tried a number of fixes that were suggested on the various posts including the loop-back test which tested good despite being unable to upload sketches.

Any idea what's going on here? This is the Arduino UNO ATmega328P.

what OS are you using?

XP

I’ll wager if you reinstalled windoze, the problem would disappear. Old computers windows getting its knickers in a twist is a fact of life. I make a goodly part of my living from sorting it. The arduino is too simple to have many problems of its own. And the fact that you can repeat the problem and solve it by following a pattern points to software.

Yes, I think I will reinstall windows. Since my first post, another problem has been encountered in that the program won't load because the comm port is being used by another program even though there's nothing else open. Hopefully, a reinstall will resolve both the "getsync" and "comm in use" issues. Thanks for the suggestion.

I suspect that the problem is your OS/Driver serial port is not allowing the DTR signal to be processed properly other then on it's initial opening. Failing to send the DTR auto-reset command to the board would give the error message you are seeing. I know that is not a solution but should allow you to focus on the most likely root cause of you symptom. You could prove this out by trying to use a manual reset switch at the proper timing when uploading and see if that works or not.

Lefty

That was one of the suggestions I had read about earlier but hitting the manual reset prior to upload made no difference.

lawren5:
That was one of the suggestions I had read about earlier but hitting the manual reset prior to upload made no difference.

Hitting and releasing the reset switch prior to hitting upload is probably not the correct timing. Usually I hold down the reset switch and release it only when I see the size of the sketch being reported at the completion of compiling the sketch but prior to the uploading task. It’s a bit tricky but can be learned.

Lefty