If I open a pdf attachment in Thunderbird and then select "Save As" in the pdf application, I get an overwrite message when using an edited existing filename. eg: If a filename xxxx.pdf exists in the folder to which I want to save and I use the name and then edit the name to xxxx2.pdf prior to saving, I get a "Overwrite existing file xxxx.pdf" message. If I select "Yes", it saves the file as xxxx2.pdf and does not overwrite the old file (so the result is what I intended). This is thus a false message, as the mechanism works correctly. I have version 24.5.0 installed on Windows 8 and Adobe Acrobat Reader XI as default. It was working correctly on my XP machine, but seemed to have changed when changing to Windows 8. When following the same steps from a file outside Thunderbird, I do not get the message.