User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_5) AppleWebKit/537.71 (KHTML, like Gecko) Version/6.1 Safari/537.71 Steps to reproduce: When I want to view a file that has been e-mailed to me, it usually easiest to find it in Thunderbird. When I double-click on the attachment, it saves the file and then opens it. If a file with the same name exists, it saves with a suffix -1,-2,-3,... Actual results: This creates needless extra copies of the file on my desktop (OS X version). Expected results: Since the attachment to the e-mail is stored locally, it could check if the attachment is the same (e.g., with diff) as the file that would be overwritten. If it is, then it can simply open the already stored version. This is my preferred behavior. To be safe, it could say "This attachment exists as file …. Would you like me to open this file or save a new copy?"

Sounds good to me, if it's technically possible without performance issues. I'd prefer to get FF's new download manager into TB, which would also help for that scenario.

(In reply to Thomas D. from comment #1) > I'd prefer to get FF's new download manager into TB, which would also help > for that scenario. bug 907732. It would make more sense to do that first (In reply to henry.pfister from comment #0) > This creates needless extra copies of the file on my desktop (OS X version). This is of course nondefault behavior - default is files re saved to %temp%