If you are moving Magento 1 sites around, this might look familiar. Especially if you are moving it to a different domain it comes to bite you while you want to log in to the backend of your site.
But, there's a way to fix it!!
First, Clear the
var/cache. and remove browser cookies.
Secondly try to use incognito mode of your preferred browser.
Now this almost never fixes this problem for me, but if you are one of the thousand. cool!
Next up, to the
app/code/local.xml file. Make sure to change the session values to write to a temp folder by doing the following:
Comment out the following:
Now, one last thing to do, remove (or set the correct) the cookie domain in the database.
DELETE FROM core_config_data WHERE path='web/cookie/cookie_domain'; DELETE FROM core_config_data WHERE path='web/cookie/cookie_path';
Clear the cache and cookies again before trying to log in again! now it should work!!