The Problem with Blogger Sitemap Files
Ideally, the sitemap file should contain all URLs of a site but if your blog is hosted on blogspot.com (or if you are using a self-hosted version of Blogger with a custom domain), you'll be surprised to know that the default sitemap file contains only the 26 most recent pages of your blog.
That's a bad thing because some of your older blog pages, that are missing from the system-generated sitemap file, may never get indexed in search engines. There's however a simple solution to fix this problem.
Generate a Complete Sitemap for your Blogger Blog
Step 1: If you haven't done this already, sign-in to your Google Webmasters account and add your blog. For details, check this video tutorial on how to add a blog to Google.Step 2: Once your blog is added to Google, open the Sitemap Generator and type the full address of your blogspot blog (or your self-hosted Blogger blog).
Step 3: What you get is list of sitemap files that contain each and every page of your blog. You now just have to ping Google, Yahoo and Bing to inform them about these XML sitemaps.
As shown in the video screencast below, you need to manually add each of the sitemap files into your Google Webmaster Tools dashboard but for Bing or Yahoo, you can simply click blue hyperlinks and these search engines will automatically download the relevant sitemap files from your blogspot site.
Once all the Sitemaps are added, your Google Dashboard should look something like this.
If you see a red cross or an orange exclamation symbol instead of the green tick, that means something is wrong with your XML sitemap. Verify that the file exists by typing the sitemap URL in your browser.
Sometimes media enclosures (like MP3 files) in blog posts can create warnings during sitemap submission. And if you have switched from Blogger to WordPress, it still makes sense to submit sitemaps of your old Blogspot blog as that will only help search engines discover your new WordPress pages. Good luck.