A feature of Firefox is that it calls your Anti Virus program to scan the downloaded files automatically upon completion of the download process. This feature is nice that it adds an additional layer of protection. However, there are times when you want to disable it. I was downloading a huge file from a trusted source. After the downloading was done, Firefox froze while the file was scanned. It took me a while to kill the crashed Firefox process.

There is no option to disable this feature in the Options dialog. You have to use the configuration editor. Here are the steps:

1. Enter about:config in the address bar and press Enter key. You might see a warning dialog. Click on I’ll be careful, I promise! to continue.
   
2. Enter scanWhenDone in the Filter box. Notice the the preference name browser.download.manager.scanWhenDone is set to the default value true.
   
3. Double click on the preference and it changes to false.
   
4. Close Firefox. The next time you use Firefox to download files, it won’t scan the files.

Once you have downloaded those files that have problems with scanning, you might want to enable this feature again.

I got a message from one of my users about Firefox this morning. The problem is that he gets a Run As dialog every time he opens Firefox. It’s kinda annoying. I thought it might be a virus or a trojan. The cause is actually harmless.

Every time Firefox opens up, the automatic update kicks in and tries to update itself. Because the user doesn’t have administrator privilege, the update fails and it prompts the user to enter a different credential. The fix is quite easy. Just update Firefox to the latest version. You can also turn off the automatic update. Therefore, you can install the updates when you see fit and the user won’t see the annoying pops up again.

In the past, I usually downloaded the latest FireFox manually for setting up machines. It’s kinda tedius and I finally decided to write a script to do it automatically. Here is the code. Note that the site doesn’t not get updated frequently. For example, the latest FireFox 3.0.4 didn’t appear at the site several days after it’s available to public. I have also modified it to download Thunderbird without a problem.

FTP_SITE = 'releases.mozilla.org'
REMOTE_DIR = '/pub/mozilla.org/firefox/releases/latest/win32/en-US/'
LOCAL_DIR = 'c:/Software/firefox/'
FILE_MASK = '*.exe'

from ftplib import FTP
import os

def handleDownload(block):
    downloaded_file.write(block)

ftp = FTP(FTP_SITE)
ftp.connect()
ftp.login('anonymous')
remote_files = ftp.nlst(REMOTE_DIR + FILE_MASK)
newestfilename = os.path.basename(remote_files[0])

if not os.path.exists(LOCAL_DIR + newestfilename):
    downloaded_file = open(LOCAL_DIR + newestfilename, 'wb')
    ftp.retrbinary('RETR ' + REMOTE_DIR + newestfilename , handleDownload)
    downloaded_file.close()

ftp.close()