Trying to fix all the things Google Webmaster Tools complains about would drive you insane. Case in point, it will warn you about soft 404s, which are URLs that don’t exist (or contain no useful content) but don’t return a 404 HTTP error code.
I had a few of these on my site where a rebuild of the postcode database meant a few old postcodes had gone missing (here’s one). Although they weren’t any links to them from anywhere, Google never forgets about pages it’s crawled. I guess I could ask Google to remove all these URLs from its index, but I have a life.
So I started returning 404 errors from these pages, hoping it would make Webmaster Tools happy and make the web a better place. Then a few days later I got a warning message from Google telling me there had been an increase in not found errors on my site. Duh, well yeh, because that’s what you told me to do.
So all I’ve managed to do is move my errors from the soft 404 bucket to the not found bucket. Ho hum. It seems like keeping Webmaster Tools happy is actually impossible.