Can’t login after WordPress 2.6.1 upgrade?
Here’s what I did!
I didn’t have that problem on this blog (i had the weird characters issue), but on one of my other blogs I couldn’t login after upgrading. I searched and tried all the suggestions given to no avail.
When I upgraded wordpress I (1) backed up my database, (2) changed the theme to default (3) uninstalled all plugins (4) logged out, (e) ran the upgrade program. After upgrade, when I tried to login, I couldn’t. It would just revert to the login screen over and over. My search began…
After reading many suggestions, I deleted all cookies, changed password, remarked out some lines in wp_config, etc etc etc.
This is what fixed it for me. I renamed my /plugins directory, cleared cookies, and was able to login. After the successful login, I re-renamed the directory to /plugins again and everything is working peachy. I reset the theme after that and everything is still working properly, I logged out and I am able to login again with success.
I really hope this helps someone! I haven’t seen this “fix” posted elsewhere.
Good luck!