Still problem with duplicate meta description

[Anton]

hi

ASP.NET 3.5

Google Webmaster Tools reports that it has found duplicate meta description
on my site. I says that mydomain.com and mydomain.com/Default.aspx has the
same meta description.

So to solve this I added a canonical link in the header of the Default.aspx
file.:
<link rel="canonical" href="http://www.mydomain.com" />

I did add that canonical link about 3 weeks ago, then my duplicate content
problem disappeared. But now the duplicate meta description problem is back
again.

So I thought maybe i should modify the canonical link to
<link rel="canonical" href="http://www.mydomain.com/" /> (see the / on the
end)

or maybe it's just googlebot being slow. Like googlebot sees the canonical
link but let it takes weeks before they take it into account....

any suggestions?