I have process builder on opportunity. On checking a checkbox i am updating fields of account using actions in process builder. Now i want that once account field gets updated the checkbox field should gets unchecked again. I am trying to add action to update the checkbox but that is not updating account fields correctly. What is the best way to do this? I want to update account fields using process builder only
Without seeing a screen capture of your process, it's difficult to give you a precise answer. I'd expect, you'd need to do a quick update of the Accounts when you update the fields, after which you'd immediately do a quick update of the checkbox value, changing it from true to false.
The issue you may be facing is that a trigger that uses this type of design would normally use a Public Static Boolean as a flag to prevent recursive re-entry. Once you do a quick update on Account, workflow could fire (check your debug logs), potentially causing another re-entry into the same process again before it finished, thus creating an infinite loop. What you're trying to do is something that may not be possible with Process Builder.
With that having been said, you could try reversing the order of events to first quick update the checkbox followed by quick updating the related fields on Account. I'm presuming they're in a collection that won't disappear once the process is started. If that doesn't work, you'll need to write a trigger that can handle the recursion.