Problem uploading to Uno when Xbee shield is attached

Hello,

I have been working with Uno's, sparkfun Xbee shields, and Xbee S2C for quite some time. A couple of days ago, my programs that work fine all of a sudden wouldn't load to one of my board setups. The error

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00

Started showing up every time. I found that I had to disconnect the Xbee and then upload the code. I upload the exact same code to another setup and it works fine.

Today, another board started failing during upload. I now need to remove the entire shield just to upload the program. I have looked up other forums, but everyone just says that you need to remove the shield. This is not feasible for my project.

I have not changed the code, I can't even upload any of the basic examples now without removing the entire shield. Did I fry something? Is there a workaround this?

Thank you.

Apparently my shield must be fried.

On one board, I replaced the shield with another one, and everything works fine. On another board I had to replace the Xbee radio, and then that one worked fine.

I have a grounding plate and I unplug the boards from power every time I put on or take off shields etc. What am I possibly doing to these things? I thought they were way more robust.