Problem using msysgit on Windows; it can't find .ssh/id\_rsa, even though it is present where it should be.

I verified that's the problem with ssh -v git@github.com; that command works when and only when I use the -i option to explicitly point it at the correct id\_rsa file but as far as I can tell, git itself doesn't have such an option; and I can't find anything either on Google or in the supplied documentation.

The peculiar thing is, it worked fine last time I used git a few months ago, and I haven't changed anything since then that seems a likely cause.

I've tried the following, all to no effect:

* Generating new id\_rsa
* Putting .ssh in current directory
* Putting .ssh in root directory
* Uninstalling msysgit and reinstalling the latest version
* Setting the HOME environment variable
* Installing TortoiseGit and trying that instead (didn't work at all)

Any ideas what else to try?