Outlook 365 error "There was an error reading the rules from the server. Th format of the server...

Copper Contributor

...The format of the server rules was not recognized"  sorry that was the end of the error, subject cut it off.


I am not new to Outlook or rules, and these are VERY simple rules.  When email arrives from Bryan Smith, move to Folder Bryan Smith.

I have several from things like Microsoft or AWS, otherwise my inbox gets so cluttered it's hard to find things.

Thing is, I have had most of these rules since last may when we moved to MS from Gsuits and never once had an error, until mid December.  Now it pops up this error for every attempted use.

Last Thursday I deleted all of my rules, and recreated a few of them, and I noticed something I saw several I did not make that just said "(client-only) and the description is "Apply this rule after message arrives" and nothing else.  When I deleted everything, that included these.  I deleted those too.  When I created a few new rules, I never selected the client only options, tried to keep it as sparse as possible, and Friday NO ISSUES!  It just worked, YAY!  Today I launched outlook to lag, and having to clock OK on that message a dozen or so times, and it intermittently popping up since.  And I have 4 (Client-Only) rules again.

I am not an expert in Outlook, but I am not a novice, and have made rules like this at every job since 2003, so I'm unsure as to how to proceed.  Any help would be appreciated.  Also some understanding as to WHY it changed to begin with.  Also I have updated Outlook, and reinstalled it too, no change.


Thanks in advance for the assistance.

1 Reply
Could you disable any add-ins or third-party software that may be conflicting with Outlook!