Hi John, are you viewing the messages in a reading/preview pane next to your inbox (folder list) or are you launching the message in a separate window?

Outlook

If you use Outlook (either on the consumer site live.com or on office.com), new message windows can be blank if you set Firefox to delete cookies when it closes. The reason is that this setting also restricts access to local storage that Outlook uses to pass data between windows. So you do need to make an exception. Here are two methods:

(1) Page Info

The easiest way to make an exception for a site is to use the Page Info dialog. While you are on the relevant page, you can call that up using either:

• Ctrl+i (for Mac, Command+i)
• right-click a blank area of the page > View Page Info
• (menu bar) Tools > Page Info

When the dialog comes up, click the Permission icon at the top to show that panel.

Cookies - Scroll down to "Set Cookies" and uncheck the "Use default" box, and then select Allow to let the site set persistent cookies.

There's no save button; you can close the dialog after that.

(2) Options page

Under Privacy & Security > Cookies and Site Data

Click "Manage Permissions", paste the relevant principal (protocol + host name) and click Allow. Then click Save Changes.

More generally, if a site is known to work in Firefox, these are standard suggestions to try when it stops working normally:

Double-check content blockers: Firefox's Content Blocking/Tracking Protection feature, and extensions that counter ads and tracking, may break websites that embed third party content (meaning, from a secondary server).

(A) Do you see a shield icon toward the left end of the address bar, near the lock icon? More info on managing the Tracking Protection feature in this article: Enhanced Tracking Protection in Firefox for desktop (before Firefox 70: Content Blocking).

(B) Extensions such as Adblock Plus, Blur, Disconnect, DuckDuckGo Privacy Essentials, Ghostery, NoScript, Privacy Badger, uBlock Origin or uMatrix should provide toolbar buttons to manage blocked content in a page. There may or may not be a number on the icon indicating the number of blocked items; you may need to click the button to see what's going on and test whether you need to make an exception for this site.

Cache and Cookies: When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Clear Firefox's Cache

See: How to clear the Firefox cache

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, click the lock icon at the left end of the address bar. After a moment, a "Clear Cookies and Site Data" button should appear at the bottom. Go ahead and click that.

In the dialog that opens, you will see one or more matches to the current address so you can remove the site's cookies individually without affecting other sites.

Then try reloading the page. Does that help?

Testing in Firefox's Safe Mode: In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.)

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" Help > Restart with Add-ons Disabled
• (menu bar) Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?