Regarding the missing buttons, that has been mentioned in a couple of threads and the only known workaround right now is to switch the message to full screen mode (on Windows, the F11 function key -- does that exist on Mac?) to show the bar.

• I have to press F11 to get the Send button to show on Office 365 since their upgrade. Any work arounds besides pressing f11
• I use Outlook Webmail, office 365 for two mailboxes. In one when I send an email it hides the top menu bar where you click send etc, meaning I cannot send email
• Outlook 365 has no functionality in Firefox.

Anything more you discover about this problem would be very welcome.

What is the script error -- could you post the specific error you see in the console, or pop-up?

If you have made changes to Advanced font settings like increasing the minimum/default font size then try the default minimum setting "none" and the default font size 16 in case the current setting is causing problems.

• Firefox > Preferences > Content : Fonts & Colors > Advanced > Minimum Font Size (none)

Make sure that you allow pages to choose their own fonts.

• Firefox > Preferences > Content : Fonts & Colors > Advanced: [X] "Allow pages to choose their own fonts, instead of my selections above"

It is better not to increase the minimum font size, but to use an extension to set the default page zoom to prevent issues with text not being displayed properly.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Some other info gathered from Microsoft's forums:

(1) Cabt send a reply because send button does not show. - Manage Office 365 - Office 365 - Microsoft Office 365 Community

Microsoft chimed in and is investigating. These temporary workarounds were noted:

• Zoom out using Ctrl- (I'm not sure whether you can immediately press Ctrl+ to zoom in again, but with many incomplete or interrupted layout problems, you can)

• Disable composing replies in the preview area, forcing replies to start in a new window (Office 365: Options > Settings > "Reading Pane" : "Type in a new window")

• Use "Light Mode": https://outlook.office365.com/owa/?layout=light

(2) Firefox - Outlook no send button when replying / new mail - Office applications - Office 365 - Microsoft Office 365 Community

These temporary workarounds were noted:

• Right-click an element in the window > Inspect Element, then close the inspector. The user who reported this was using the Firebug extension, but it might work with Firefox's built-in feature as well.

• Full screen: F11 on Windows or Ctrl+Command+f on Mac

• Press Ctrl+Enter to send (Windows? maybe Command+Enter on Mac?)

Note that this can be caused by using as wider font that takes more space. I don't know which font is specified and which font is used on a Mac for that menu bar (the specified font may not be available and Firefox falls back to a wider font). I've seen items on that menu bar disappearing with an increased minimum font size and if zooming out is suggested as a workaround then this appears to be happening.

Yes, Command/Enter will send the e-mails on a Mac.