Many site issues can be caused by corrupt cookies or cache.

• Clear the Cache and

• Remove Cookies
  Warning ! ! This will log you out of sites you're logged in to.

Type about:preferences<Enter> in the address bar.

• Cookies; Select Privacy. Under History, select Firefox will Use Custom Settings. Press the button on the right side called Show Cookies. Use the search bar to look for the site. Note; There may be more than one entry. Remove All of them.
• Cache; Select Advanced > Network. Across from Cached Web Content, Press Clear Now.

If there is still a problem, Start Firefox in Safe Mode {web link} A small dialog should appear. Click Start In Safe Mode (not Refresh). While you are in safe mode;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Poke around safe websites. Are there any problems?

Then restart.

Can you attach a screenshot?

• https://en.wikipedia.org/wiki/Screenshot
• https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem

• use a compressed image type like PNG or JPG to save the screenshot
• make sure that you do not exceed the maximum size of 1 MB

See also:

• https://support.mozilla.org/kb/Website+colors+are+wrong
• https://support.mozilla.org/kb/Changing+fonts+and+colors

I have finally returned to the users computer, captured screen shots of some of the issues. Also, Inserting an image into the email and then mouse out/in in the body of the email causes the image to disappear, then reappear on mouse out. in box did the same! The inbox fonts look all choppy, then perfect at times with no changes.

I have uninstalled Firefox, deleted the app data folder, reinstalled and still same problem.

Notice the home page and email imaged that are attached.

Thank You, Doug

See if there are updates for your graphics drivers https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

I've updated graphics driver, shut off hardware acceleration, and receive the same results. The weird thing is that Chrome displays the yahoo home page correctly, as well as the yahoo mail. Firefox seems to have the graphics issues.

Update your Flash Player Note: Windows users should download the active_x for Internet Explorer. and the plugin for Plugin-based browsers (like Firefox).

Note: Windows 8 and Windows 10 have built-in flash players and Adobe will cause a conflict. Install the plugin only. Not the active_x.

Flash Player Version: 22.0.0.209 Flash Player (Linux) Version 11.2.202.632

https://get.adobe.com/flashplayer/ Direct link scans current system and browser Note: Other software is offered in the download.

https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download.