What application are you using to manage your emails?
There 'may' be an option in Tools > Options to set the default location, but on my own Thunderbird email software I can't see that option.
So, if not, the application may be remembering the 'last opened location', and there is not much you can do about that. My Thunderbird always opens to my Desktop location, so I always place the files I want to attach onto the Desktop. That way I don't have to browse elsewhere.
The alternative is a workaround. Using Windows Explorer, (I assume you are using a Windows OS), navigate to the folder you want the dialog to 'always go to'. Right click that folder then select "Send to.. Desktop (Create Shortcut)".
Now, navigate to the folder that your application 'always opens', and drag that newly created shortcut into that folder.
The next time you open that dialog you will see this shortcut, and you can simply click, (or double click), it to be taken straight to the folder you want.
Hope that helps.
I have an Inspiron 1545 and have a problem whenever I send attachments through e-mails. When I am sending multiple attachments in one e-mail, the Attach file dialog box never opens at the file from where I opened the previous document. I have to continually direct the dialog box back to that folder, where my other, older Inspiron model will always open at folder where I was previously. Any ideas as to how I can configure the Attach file dialog box?