Windows doesn't want me to write a file there (I get an error).

You can manually type a path as a workaround:

C:\prn\filename

But that is annoying to do every time... Someone did file a request to attach a Windows file browser dialog to that box — in January 2008. (Bug: 413537 – "Print To File" should provide standard file selector) Obviously it has not been prioritized, perhaps because few people use this feature.

Why do you use Print to File, and have you considered alternatives such as PDF and XPS?

If you're interested, some free PDF printer drivers are listed in this thread: How can I print to a file? Msg: "Could not open the file, access denied".

About the bug tracking system: it's generally not helpful to add "me too" and "hurry up" comments to bugs, but you can register on the Bugzilla site and "vote" for them to be fixed. See:

• Bugzilla Etiquette
• Voting

I am trying to save emails from my yahoo mail by printing them to a file.

This is not solved as I do not know where to change the default directory.

Don't use Print to file, use something like Save Page As... in the Contextual Menu or in the File menu to save to HTML format. Or install a Print to PDF utility program or extension so you can save the email to PDF format.

See - Print to PDF extensions

You can try to change the default working directory via the Properties of the Firefox desktop shortcut.

Hi Tai4firefox, you wrote:

This is not solved as I do not know where to change the default directory.

You cannot do this without modifying the program code of Firefox. So you should consider other options.