Some times we have issues whith Magento reindex, the page shows reindex processing and we can´t  run again

This are 3 steps to resolve :

1. go to  [Magento_installation]/var,  enter with SSH and run :

chown apache locks

Where apache is the server user, on Ubuntu can use www-data instead.

Other solution less secure if this not works

chmod -R 777 locks

2. Enter in locks folder and delete files inside

cd locks;
rm -r *.*;

 3. Using the shell command :

go to  [Magento_installation]/shell and run :

php -f indexer.php -- reindex all