Forum Discussion
Microsoft 365 Outlook Classic Latest Update Copilot issues
Hello to all, we are currently using the Microsoft 365 Outlook Classic, using version Version 2604 Build 16.0.19929.20172 (Current Channel) Copilot works as expected;
However ever since the next update was released (Version 2605 (Build 20026.20076)) some users including me, have been getting the below error:
I have tried uninstalling and installing the latest version directly, with the same issue. Scanned for any corrupted system files with no issues,but still get the error; I have tried the update Licence from the Outlook application, with no issues but the copilot something went wrong error keeps on persisting. Internet searches are very vague and the I have found some registry suggestions which I have also tried with no solution.
The only way to get Copilot working on Outlook Classic was to revert to a previous working version, only then Copilot works as expected. This only happens in Outlook Classic; Copilot works fine on the latest version of Microsoft Office 365 with Word, Excel, etc.
For those that maybe might ask why not switch to the New Outlook, we have had issues with it and it has been recommended to use the Classic Outlook for the time being.
Has anyone been experiencing such issues please?
Thanks for any help.
11 Replies
Yes, this is a known issue after some recent Outlook Classic + Copilot updates in Microsoft 365. Many users are reporting slow performance, sync problems, or Copilot not loading properly after the update. In most cases, it can be fixed by restarting Outlook, checking for the latest Office updates, or repairing the Office installation. If the issue still continues, creating a new Outlook profile or rolling back to a stable version often helps resolve it.
I had tried all the above you mentioned and nothing made copilot work; Update / refresh License in the outlook classic app, uninstalling and re installing office, install the latest update available, including the creation of a new profile.
Just this morning I noticed that it worked out of the blue.
Just now , I got the notification that a new update is available (Build Build 16.0.20026.20140), installed it, and copilot still works. However I will keep my eye on it from time to time.
Not sure what solved it, but it seems that the installation of the general copilot app on my laptop might have changed something.
Again this is just what I am guessing and what I experienced first hand.
So without doing anything, just this morning I gave the copilot another try thinking that the same error will occur, but to my amazement it is working ! Also the layout is different, instead of the text box it comes up as a prompt as in the below screenshot:
It just worked ! Will keep an eye out in case it gives me the same issue as before but for now it seems to be fixed, without doing anything.
One thing I just noticed, is that the copilot app was recently installed without me doing anything once again; not sure if it has any effect on the outlook app issue, since this was solely related to Outlook (Classic) but wanted to mention this just in case..
Hello, as of June 2, 2026 the issue is back .. it was working fine late last week. Any updates as to when this issue will be resolved?
We are also having the same issue
My organization is experiencing the exact same behaviour in Outlook Classic, just with the "Coaching" feature - other Copilot features are working. Our workaround is to use Outlook for web or Outlook New. I have reported it to Microsoft for investigation.
We also facing the issue for all orgnization user who have Microsoft Copilot Pro license, pls check and provide the solution. Its impacting
I was facing the same issue earlier. After switching from Classic Outlook to the New Outlook, I was able to use Copilot successfully.
A new update has been released:
Version 2605: May 26
Version 2605 (Build 20026.20112)
However the issue still persists; good to know it seems we are not the only ones experiencing such issues.
Awaiting any feedback on a possible fix for this issue please...
Our organization is also having the same issue w/ the same build Version 2605 (Build 20026.20076). Seems to be working in all apps except outlook and getting the same error as described above.
please solve asap, all the users with the 20026.20076 are affected
