(Modifying the title to provide clarity)
I have edited multiple rules in Outlook for Mac and when trying to save the changes I get this error message:
"Rules could not be saved because there is an error in the rules. Edit the rules, and then try to save the rules again."

What? I mean WHAT???
Firstly, I have edited the rules in your UI and clicked OK after each edit, how can there be an error?? Why did you not check for errors when I pressed the OK button? How is it even possible that your UI lets me create a rule with an error, it is not a programming
language, it is a user interface!
Secondly, what an ignorant unhelpful error message is this? What is the error? In which rule it is? How do I fix it? The message could have equally read "F... YOU!", it would be equally unhelpful and rude!
Not only did I have to abandon all the changes I made, you have also ruined my day!
I HATE YOU TOO MICROSOFT!!!
The easiest fix is to log into your online account with your browser to office365.com or outlook.com depending on what you are using. I'm using 365 and outlook setup on exchange. So, I just logged into https://login.microsoftonline.com/
then...
- On the top right side, click the Gear Icon
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- then click the 'mail' link at the bottom of the page on the right side menu under 'App Settings'
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- Now move to the left menu on the page and choose 'Inbox and Sweep Rules"
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This will open the rules that are synced with your Outlook. Any errors should have a yellow warning triangle between the checkbox and the rule name "to..".
My problem was a folder i had deleted so i just deleted the rule and saved. Went back into outlook and easy-peasy rule creations without errors.
Now, if you have more than one account setup in outlook, you may have to do this for each one to find the offending rule.