To turn off the Virusscan
- Navigate in Firefox to the address bar and type the Text "about:config". Confirm the security note.
- Enter in the "Find:"field, the term "Scan".
- The first recorded entry in browser".download.manager.scanWhenDone". Under "value" is this entry to "True".
- To set this entry to "False" and, therefore, to disable the Scan, double-click on the entry.

 Virusscan on Firefox shutdown
 
Has been tested on Firefox 23.0.1. As you saved passwords in Firefox to delete, you can learn here.






