Outlook 365 Rules error message

Question

Your advice as to how to identify/fix this Outlook 365 error message will be much appreciated:

"There was an error reading the rules from the server. The format of the server rules was not recognised."

Answer 1

Hi @David Elliott ,

Probably, some rules have been corrupted.

If there are not many rules in the mailbox, you could recreate the rules.

You can also reset the rule engine and then rebuild the rules.

https://social.technet.microsoft.com/Forums/en-US/f88d1841-2c6b-4ee6-9ed9-e441c2bbc60e/there-was-an-error-in-reading-the-rules-on-the-server-the-format-of-the-server-rules-was-not?forum=exchangesvrclients

Answer 2

Do you get this error when trying to edit a rule in Outlook client for Microsoft 365?
Does it affect other users in your environment?

Please check for and install all available updates via File > Office Account > Update Options > Update Now to ensure that your Outlook client is up-to-date.

Besides, agree with TKujala that this error might be caused by some corrupted rules, if you continue to run into this issue, please try recreating the rules as mentioned by TKujala and see the result. In case the rules cannot be deleted manually, you can run an Outlook command when you start Outlook by running "Outlook.exe /cleanrules". (Note: This will delete both the client and server rules and will delete all of the rules for all of the accounts in the Outlook Profile.)