Care to explain what you did?

1. Apply filter when: Manually Run checked and getting New Mail is checked.

2. Select a message from a sender I wish to block, right click on sender's address and choose Create Filter From...

3. Open the Filter rules window with the email address inserted into the window underneath “Match all messages”

4. Click OK to to save the filter, the next time that person sends you mail, it will automatically be deleted

that appear to differ from the instructions here https://support.mozilla.org/en-US/kb/blocking-sender

Primarily you make no mention of changing the action on the filter to delete mail from that address.

Hello Matt and thanks for your response! I thought I was following the Mozilla instructions to the letter, maybe you can tell me how to go about "changing the action on the filter to delete mail from that address".

This is the process to use the first time: Right click on a 'From' email address in email header and select 'Create filter from'.... a new window opens 'Filter Rules' Give filter a name - suggest 'Delete Sender' or similar. I prefer the name 'Delete Sender' because that is what is occurring, but it's up to you.

Apply filter when:

• Manually Run
• Getting new Mail and select 'Filter before Junk Classification'
• Select 'Match all of the following'
• The 'FROM' and 'Is' is selected and the email address will be auto entered.

Perform these actions: Choose one of the following options:

• # Move Message to and choose the account Trash folder (which may be called Bin or Deleted etc)
• # 'Delete Message'
• Click on OK

If you have already created a 'Delete Sender' filter (and need to edit anything OR want to check the filter is enabled) :

• 'Menu app icon' > 'View' > 'Tools' > select 'Message Filters'
• Select the 'Delete Sender' filter and click on 'Edit'

If you want to add another email address:

• Select 'Match ANY of the following'
• click on the far right + button
• Select 'FROM' and 'Is' and enter email address.

If you want to check the actions are correct: 'Perform these actions' Choose one of the following options:

• # Move Message to and choose the account Trash folder (which may be called Bin or Deleted etc)
• # 'Delete Message'
• Click on OK

• Click on OK to save and close filter.

You will now see the 'Message Filters' window.

• Make sure the filter name is enabled by selecting the checkbox - otherwise it will not run.

If you want to test filter by running manually on a desired folder: Select the filter

• 'Run selected filters on : Choose the relevant folder on that account eg: Inbox'
• Click on 'Filter Log' - it opens in a new window - select checkbox 'Enable the filter log' and click on 'Close'
• Click on 'Run Now'.