I have the same problem too. In Chrome and Firefox the canvas snapshot download works fine, but when it comes to IE.... a new tab is opened with the image specifications as url and the download never starts. The url is the following:
data:image/png;base64,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
Any ideas about how to solve it?
Thanks!