I have created a custom region called latest. And when I am assigning some block to that region from admin, while saving it returns this error
Region for Main page content block field is required.
What might be the reason?
I did a search for the error message "region for main page content block field is required" which produced theses results:
drupalgardens.org: Region for Main page content block field is required
An issue on drupal.org: "Error MSG: Show block for specific content types field is required". Are you running the "Superfish" module? The error seems to be related to that.
It appears that you need to assign content/block to the "Main page" region as it's currently empty.
This post helped me get closer, but I thought I would provide a more concise answer for those following the same path.
If you are looking to remove all blocks from Drupal 7, like you would want to do if you were placing blocks by using Context, you want to make sure that core's "Main page content" is the last block removed.
To get rid from this error, just assign a "main page content" block to the content region in administrator >> structure >> blocks; then press the "Save block" button at bottom.
Looks like the region
content is compulsory in the theme-name.info file. I added that and everything got solved. Just had to add the following
regions[content] = Content
You could use the Context module for assignment of blocks, make sure to remove the Main content block of the blocks overview page as the last one.
Just enable the "Main Content Page" block in Structure>Blocks then save. That will save the problem.