When Magento starts indexing of each item in the ‘Index Management’ list it sets ‘status’ field of correlative entire of ‘index_process’ table to ‘working’. If error happens during the indexing process script halts and status remains as ‘working’. As a result ‘processing’ image hangs at the ‘Index Management’ page. Of course there’s no way to make sure that indexing process is still not running but checking your server’s processes list (or brutal restarting or your apache).
The only intelligent way I know to solve this issue is to find out what causing this error and fix it. You can do it by running indexing from your shell and looking for the output. Here is the command:
php shell/indexer.php reindexall
If you don’t have an SSH access you can also try locating this error from your server’s error logs.
If you just want to remove ‘processing’ image you can just run the following MYSQL query:
UPDATE `index_process` SET `status` = ‘pending’ WHERE `status` = ‘working’
However this will not solve the problem, but only hide the output.