Gmail default for mailto links in Google Chrome (Windows)

Update:
Approach might break, as Microsoft Outlook seems to be overwriting this registry key on a regular basis. I’ll update this post with a more solid approach sooner or later.

It’s a small annoyance, but I’d prefer to have my mailto: links open a compose window in Gmail, rather than waiting for Outlook to start. Furthermore then personally I’d rather not have to install apps such as “Google Toolbar”, “ChromeMailer” or “Google Notifier” simply to have my mailto links do what I want, which I know is the solution many people resort to.

On Windows however a mailto: link is just like any other file type, so you can set the default application for that file type. In theory you could go through the a bunch of menus in the file explorer change the settings there, but who wants to do that when you can just apply the change directly in the registry with a single click (more like 6 actually)?

Anyway here’s the content of the registry file (right click and save as gmailto.reg):
Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Classes\mailto\shell\open\command]
@=hex(2):22,00,25,00,55,00,53,00,45,00,52,00,50,00,52,00,4f,00,46,00,49,00,4c,\
00,45,00,25,00,5c,00,4c,00,6f,00,63,00,61,00,6c,00,20,00,53,00,65,00,74,00,\
74,00,69,00,6e,00,67,00,73,00,5c,00,41,00,70,00,70,00,6c,00,69,00,63,00,61,\
00,74,00,69,00,6f,00,6e,00,20,00,44,00,61,00,74,00,61,00,5c,00,47,00,6f,00,\
6f,00,67,00,6c,00,65,00,5c,00,43,00,68,00,72,00,6f,00,6d,00,65,00,5c,00,41,\
00,70,00,70,00,6c,00,69,00,63,00,61,00,74,00,69,00,6f,00,6e,00,5c,00,63,00,\
68,00,72,00,6f,00,6d,00,65,00,2e,00,65,00,78,00,65,00,22,00,20,00,20,00,2d,\
00,2d,00,61,00,70,00,70,00,3d,00,68,00,74,00,74,00,70,00,73,00,3a,00,2f,00,\
2f,00,6d,00,61,00,69,00,6c,00,2e,00,67,00,6f,00,6f,00,67,00,6c,00,65,00,2e,\
00,63,00,6f,00,6d,00,2f,00,6d,00,61,00,69,00,6c,00,3f,00,65,00,78,00,74,00,\
73,00,72,00,63,00,3d,00,6d,00,61,00,69,00,6c,00,74,00,6f,00,26,00,75,00,72,\
00,6c,00,3d,00,22,00,25,00,31,00,22,00,00,00

What this does is change the key HKEY_CURRENT_USER\Software\Classes\mailto\shell\open\command to be of type REG_EXPAND_SZ and with the value “%USERPROFILE%\Local Settings\Application Data\Google\Chrome\Application\chrome.exe” –app=https://mail.google.com/mail?extsrc=mailto&url=”%1″.
Changing the key type to  REG_EXPAND_SZ expand the environment variable %USERPROFILE%, so you don’t have to manually type in the path to your user profile directory.

Normal disclaimers apply to changing stuff in the registry and also you should probably consider checking for yourself if the hex values actually correspond to what I claim, for example by using this hex to string tool.

Different platform? Same idea. E.g. on Ubuntu Linux change settings in System > Preferences > Preferred Applications.
Different default browser? Same idea, just change path and however it likes its command line arguments.

References:
Google Chrome suggestion thread