It's not for blog posts, though.
When you start to see double in your blog, chances are that you duplicated the Blog Posts entry in the template. It's not hard to fix, fortunately.
Edit the blog template HTML, using the dashboard Template Editor, at Template - "Edit HTML". Do not check "Expand Widget Templates". Look for two lines, in the Body of the template:
<b:widget id='Blog1' locked='true' title='Blog Posts' type='Blog'/> <b:widget id='Blog2' locked='true' title='Blog Posts' type='Blog'/>Remove:
<b:widget id='Blog2' locked='true' title='Blog Posts' type='Blog'/>Leaving:
<b:widget id='Blog1' locked='true' title='Blog Posts' type='Blog'/>
Save the change. You will get a stern warning when you save, demanding that you confirm that you really want to delete "Blog2". Obviously, you do. And don't forget to clear browser cache, and restart the browser, to reliably test your change.
Remember to save a copy of the template, before and after doing this.
And now, since you're here, and if you just removed a duplicate post template from your blog, help me to help others, and think why you're here.
- What changes have you made, to the blog?
- What accessories have you installed?
- Any templates - Blogger or third party? - installed?
- Any changes between classic and layout templates?
- What Blogger features / wizards do you use?
- Draft Blogger?
- New, or Old, Post Editor?
- What third party services have you ever allowed to access the blog directly, to install something?