Blank screen ufter upgrading to 2.9

I had the same problem after the upgrade to 2.9.1 hung. Fixed it pretty easily, thanks to others who had the same problem. I downloaded 2.9.1 to my computer, and then deleted wp-admin and wp-includes on the server. I uploaded the root files and the wp-admin and wp-includes folder. After that it worked. I also could go into the control panel. It warned me that the database needed updating, and that worked quickly without issues. Thanks!

this helped… but not much.

at first, I was getting this error:
Warning: Cannot modify header information - headers already sent by (output started at /public_html/index.php:1) in /public_html/wp-includes/pluggable.php on line 868

which contains this:
header("Location: $location", true, $status);

after using the mentioned plugin to disable redirects, now I’m getting this other header error:
Warning: Cannot modify header information - headers already sent by (output started at /public_html/index.php:1) in /public_html/wp-includes/feed-rss2.php on line 8

which contains this:
header('Content-Type: ' . feed_content_type('rss-http') . '; charset=' . get_option('blog_charset'), true);

any ideas, besides the downgrade?

Solving “headers already sent” warnings

From your link Esmi: “Also check the encoding of the file. If the file is encoded as UTF-8 with BOM, the BOM is seen as a character which starts the output.” – and guess who had an index.php saved with UTF-8 with BOM?

removed it and my rss came back like a charm. thanks a lot! =D

Mine was a missing htaccess file. I had published a new page and all the pages went blank … turns out my htaccess file somehow disappeared. (Viewing source doesn’t do anything in this case – the “source” is just a blank page too.)

I went into Settings > Permalinks, resaved those settings, and the problem was solved.

My clue in it being higher up than the theme level is that 1) the page came back blank very fast – no load time, and 2) I switched to the default theme and had the same problem.