How do i fix "This site requires a security code to sign in. When your security info updates on 4/21/2021 you will be able to access this site. You can still access sites such as Outlook and Skype that don't require a security code."

START OUTLOOK OFFLINE WITHOUT INTERNET ACCESS: (Best for Microsoft Exchange Mailbox situations)

1. Click Start > Type outlook.exe > Right click > Open File Location
2. Shift Right Click on Outlook > Copy As Path
3. Windows Key + R (to open Run Box) > type wf.msc and click ok.
4. RIGHT click "Outbound Rule" > "New Rule"
5. Program > Next
6. This Program > Ctrl V > Remove the double quotes at the beginning and end. > Next
7. Block the Connection > Next
8. Name it something: BLOCK OUTLOOK > Finish

You can now run outlook offline without having to changing stuff in the registry. The registry option isn't hard, but it's a hex entry which can be difficult to handle. AND, blocking it with the firewall guarantees no inadvertent deselecting "Work Offline." You will see at the bottom right that Outlook is just "disconnected." The "Work Offline" mode will not be enabled, but your Outlook will have no internet access.

When you're done trying to salvage the career-ending email from going out, you can do the following to undo the outlook block.

1. Windows Key + R (to open Run Box) > type wf.msc and click ok. (Assuming you already closed it)
2. Click Outbound
3. Right Click BLOCK OUTLOOK > Disable Rule (or Delete if you don't think you'll ever need it again).

So how do I open Microsoft Outlook In Offline Mode? The above solution only works if Outlook is already running!

in outlook 2019 I have a problem with icon of forwarded messages when i forward a mail it doesn't appear on the column the icon of fw message

"Open Microsoft Outlook In Offline Mode" - proceeds to tell how to change to offline mode AFTER the application is open. Quite different to the subject.

How to convert OST to PST for free?

With Win10 Settings Panel you can now set a Network Adapter as "Metered" - When in "Metered" State, Outlook will not connect. Confirmed in 2013/2016. Along the same lines as MV's post but would still provide network access to other items. However if your IT admin has prevented you from modifying computer settings, you can also pull a network cable or turn off Wi-Fi, unplug wireless router.

@DW... Strongly tempted to not respond given your attitude, but did you try my suggested method - immediately above your comment? Pretty sure that would work...

Step 1 doesn't work (Office 2010). Step 2 works fine if you are already running Office. Useless explanations.

I have a workaround, for Office 2016 at least - "Disable" all network adapters (inc. wireless), and then open Outlook. Once Outlook is open, you can set it to "work offline" and re-enable the network adapters.