I guess that the following problem had happened to most of us, so I want to write down the solution I followed: The search service was throwing errors in the home, so I decided to enter to the server to see what was happening and I realized that the password for the managed account has expired. So, I tried to changed, but I received the following error:
The password for the account domusermss, as currently stored in SharePoint, is not the same as the current password for the account within Active Directory. To fix this with PowerShell, run Set-SPManagedAccount -UseExistingPassword.
So, the password for the account I am using to run the service using has been changed in AD, this does not match the password stored in the SharePoint.
One possible solution is to reset the password in the AD or the other solution is to use PS
Set-SPManagedAccount -identity “domusermss” -UseExistingPassword and enter the new credentials.
After that remember to change the password stored in the services of the server, if not will not be possible to start the services associated with the identity of this account.
Hope it helps!
Albandrod's Memory 
What if you forgot what the password was? Is there a cmd that allows you to use something else other than the -UseExistingPassword ?
thankss
LikeLike
Hi Tom, after you specified the command -Useexistingpassword you can specify the new credentials for the managed account, so is it not a problem. If you have any doubt, please let me know and I will try to help you 🙂
LikeLike