Running Outlook on the iMac causes the screen to flicker and eventually black out and reduce to half/split screen display.

We are also having what appears to be the same issue with 2 of our iMacs.  Both 27"5K Late 2015 models that flicker intermittently and sporadically.  When the issue happens the user has to force shutdown.  The issue disappears for a few days then returns. 

We use Outlook heavily here.  We are part of a wider group of companies that has heavily invested in Office 365 and the host of apps that come with it.  Outlook has been working fine for the most part.  We have tried clean installs on the two computers but the issue persists. Apple Genius Engineering Team could find no Hardware faults and summised software was the cause.  The only programs that the 2 users always have open are Safari and Outlook. 

We will see whether the issues occur without Outlook, but our users won't be happy as Outlook is integral to the way they work. 

Please  update if a fix/patch is found/released.

Your description typical what occurs.

As an individual business owner not reliant on Outlook and have moved to  Apple Mail ....no issues now and my Mac has never been this well behaved and  fast!!

We are also having what appears to be the same issue with 2 of our iMacs.  Both 27"5K Late 2015 models that flicker intermittently and sporadically.  When the issue happens the user has to force shutdown.  The issue disappears for a few days then returns. 

We use Outlook heavily here.  We are part of a wider group of companies that has heavily invested in Office 365 and the host of apps that come with it.  Outlook has been working fine for the most part.  We have tried clean installs on the two computers but the issue persists. Apple Genius Engineering Team could find no Hardware faults and summised software was the cause.  The only programs that the 2 users always have open are Safari and Outlook. 

We will see whether the issues occur without Outlook, but our users won't be happy as Outlook is integral to the way they work. 

Please  update if a fix/patch is found/released.

A further update and Observation.   If you change the resolution of your screen away from the 5K default, the problem also revolves, whilst not ideal it is a work around if you are dependent on Outlook.  Please also see a message from Outlook Team

Good day once again, Jonathan. Hope all is well from there. Thank you so much for the update.

This behavior is a bug that we are currently investigating. I have added your ticket to the bug list so it gets further investigated by our development team. We are unable to provide you an estimated time for a fix to be released for this bug but rest assured that we are working on it as we speak. Our bug fixes are normally released in a form of an update so just continue to keep Outlook updated to get the fix as soon as it is released.

You may keep  yourself abreast with Insider Fast bug fixes and improvements release notes by visiting the link provided below:

https://support.office.com/en-us/article/outlook-for-mac-release-notes-for-insider-fast-builds-d6347358-5613-433e-a49e-a9a0e8e0462a?ui=en-US&rs=en-US&ad=US

Please let me know if you have other questions or suggestions related to Outlook for Mac. Also, please let me know if you will allow us to archive this ticket while the bug is being investigated. Thank you for your understanding.

Ok, keep me updated if your issue fixed by reverting back to 16.24 .

I have been running like this for some 5 hours and no issues -yet!

If re-appears, will post accordingly .

Really do not think it is a hardware issue .

Regards.

Alan.

Been running Outlook version 16.24 after reverting back from 16.25  for three days now and issue of screen flashing has not re-appeared again.

This fix applicable to a late 2015 27" iMac - whether this applies to laptops ,other iMacs of a different vintage  etc. I really do not  know,  but now fixed on my iMac .

Hi,

I tried the downgrade today on my Macbook Pro with external 4K Monitor. Sadly the flickering came back after half a day having Outlook opened on the external Monitor...

Mine also came back sporadically with 16.24 after some days of stability , but much less than before ..Tends to happen in Outlook when you open a mail item in a dialogue box and then scroll ...this  is when it starts flashing  .

My problem is resolved though -converted to Apple Mail .

No more issues !!

Having downgraded to 16.23, I too get occasional flickering, requiring a logout.  However much less severe and less frequent. No issue with Apple Mail, but with Office 365 a lot functionality is lost.  Microsoft really need to sort this.

Ok, keep me updated if your issue fixed by reverting back to 16.24 .

I have been running like this for some 5 hours and no issues -yet!

If re-appears, will post accordingly .

Really do not think it is a hardware issue .

Regards.

Alan.

Been running Outlook version 16.24 after reverting back from 16.25  for three days now and issue of screen flashing has not re-appeared again.

This fix applicable to a late 2015 27" iMac - whether this applies to laptops ,other iMacs of a different vintage  etc. I really do not  know,  but now fixed on my iMac .

Hi,

I tried the downgrade today on my Macbook Pro with external 4K Monitor. Sadly the flickering came back after half a day having Outlook opened on the external Monitor...

Mine also came back sporadically with 16.24 after some days of stability , but much less than before ..Tends to happen in Outlook when you open a mail item in a dialogue box and then scroll ...this  is when it starts flashing  .

My problem is resolved though -converted to Apple Mail .

No more issues !!