Using Mamp, duplicated my 3.4.9 production site locally. Ran the 4.1.10 update everything went fine, no errors including the DB conversion. Can log into the admin center no problem but when I go to the site other than the main forum page, I get "Not found, the requested URL  /p15d24ph_forum/forum/4-p15-d24-forum/was not found on this server". If I try to log in I get a p15d24ph_forum/login/ as not found.."  Every page I try to access has the same error.  It's still running all the background processes if that makes a difference. 

What did I miss? 

 

Tried this again but disabled all third party plugging and apps before running the conversion. Again no error during the entire process, but same results. 

Did you check your .htaccess file? Just a wild guess.

Nothing there but deny from known troublemakers. 

Did you have friendly url rewrite enabled and was this config carried across? 

Yep, that was it.