Make sure that Screenshots isn't disabled.

You can check these prefs on the about:config page (both should be false).

• extensions.screenshots.disabled = false
• screenshots.browser.component.enabled = false

Taking screenshots can also be disabled via a policy (see about:policies).

You can open the about:config page via the location/address bar. On the warning page, you can click "Accept the Risk and Continue" to open about:config.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

Thanks, that helped a little. Now when I right click, the screenshot option shows, but I still don't see the screenshot button in the toolbar buttons. It was there a few days ago.

Did you check the customize page if you can see the screenshot button in the Customize palette and drag it to the toolbar ?

• if missing items are in the Customize palette, drag them back from the Customize page to the toolbar
• if you do not see an item on a toolbar and in the Customize palette, click Restore Defaults in the Customize palette window to restore the default toolbar set.

• https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars

I thought I explained in my last comment that I don't see the screenshot button when I look at the buttons. Anyway, it's not there. When I clicked on Restore Defaults, I still don't see it. It has completely disappeared.

You can try to reset browser.uiCustomization.state on the about:config page (i.e. click the trash icon on this line).

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

Are there any screenshot related messages in the Browser Console (not the Web Console) ?

• https://firefox-source-docs.mozilla.org/devtools-user/browser_console/

Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or if userChrome.css/userContent.css is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window

• https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Now it's back in my list of buttons. For some reason it reappeared. I didn't change any settings. Thanks for your help.