New
#21
I guess there is two ways to approach this if the DISM command did not work.
If the goal is to stay with ATT/Yahoo account use Firefox with your current ATT/Yahoo account. This is the easiest and Firefox is an excellent browser. It works and you should be able to set home page with mail and just use. (Wait for the powers to be to fix ATT/Yahoo on Edge. There are threads within forum outlining different Edge issues. )
The other alternative is to move away from a Yahoo account and open a Outlook.com account (maybe you have one or an older hotmail, msn or live Account). This has the benefit of not being tied to supplier (ATT) so your mail becomes independent of ISP.
Open an Outlook.com account if you don't have already. Use Firefox to gain access to your Yahoo account. Click on the gear, upper right, click settings, Click Accounts, Click your ATT account. This should open a window that allows you to forward your mail to a new account. You can keep a copy on Yahoo or not. I like to keep a copy so I can see who is send to old address in a months time and I check regularly
After changing scroll to bottom and save.
If it takes you back to mail go back into settings and this time update Vacation response to tell people you are moving or if this is temp.
If you open Edge and set Outlook.com as home page you should see all new mail as it arrives.
Ken