There is a bug in Google AdWords that will prevent you from downloading or printing reports from the AdWords console. I tested it myself and I received the following error:
There was an error with your operation. If you were trying to make a change, it may not have saved. Please refresh this page to try again. If the error continues, log out of your AdWords account, then log in again and return to this page.
The report has been confirmed by Cassie at Google in this Google AdWords Help thread. Cassie wrote:
This is a known issue that the engineers are working to fix. Thanks for flagging!
Here is a screen shot of the download feature:
It is unclear as to when this will be fixed.
Forum discussion at Google AdWords Help.
For anyone experiencing issues downloading reports via the AdWords UI, the issue is fixed. We'll continue to monitor for unusual behavior.— Google AdWords (@adwords) February 26, 2016