I've noticed this when downloading a file when a file with the same name already exists in the destination directory. Since you aren't saving the file first, the existing file is probably in a temporary directory (as opposed to a "user" directory you would be familiar with, like %USERNAME%\Downloads)
I asked this question on MS Forum This was the reply i got.
Excel is crashing because of the invalid special characters in the name of the file. This is clearly seen in the below snapshot with the description of what all characters are considered invalid. If we try saving a new Excel file in Excel 2013 as Test.xlsx (with square brackets) and some content in it, then we get the below message. So after renaming the file without these characters, it fixes the issue.
Question: Why does Excel care what the file’s name is on the file system?”
Answer: Because it denotes the workbook name in any link paths. Therefore it will mess up parsing links which then gets into messing up calculation.
When I try to download a excel file from .net application its not appending  version after the file name ..But our application based on java.Its causing the issue .
Can any one help me on this.
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