I have a problem with an Arduino Mega 2560 board (SainSmart). The IDE gets stuck at the "Uploading to I/O board..." message. The bargraph shows around 95% but then there is no further progress. I tried this with Windows 7 64bit and Win XP, with 101 and 0023. Uploading is impossible. Board type and COM port are correctly set in the IDE. Any ideas to solve the problem?
The normal reason for a failed upload on a Mega is the use of "!!!" somewhere in your code. The most common seems to be this.