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

So far the low-resolution works for the two iMacs here.

I find that interesting that the Outlook app would actually have an option to run in low-resolution? Why would someone select that option on purpose? Was there an issue in the code with high-resolution displays and Microsoft engineers just threw that option in, in case someone had that problem?

As far as "first time to hear about it," I guess we all need to keep reporting to this thread and maybe they'll notice the views and comments, and do something for us.

Apple replaced my logic board twice and display once under AppleCare for this issue. Over $2,000 on Apple's dime for parts and labor. This is hilarious that neither Microsoft's Office team or Apple is flagging this issue for their technicians.

I have got the same problem too. I have sent an email to Office 365 support and they said this is their first time to heard about this issue. It seems that this forum is more professional than the engineer in Microsoft.

They suggest us to lower the resolution but this is no the answer I want to have.

Are there anyone has come up to a real solution yet? If so, please kindly share.

Thank you!

Right after the June 11, 2019 release of version 16.26, I had two late 2015 iMacs that started to flicker.

4.0GHz Quad-Core Intel Core i7

16GB 1867MHz DDR3 SDRAM

AMD Radeon R9 M390 with 2GB

OS X 10.14.5

4.0GHz Quad-Core Intel Core i7

16GB 1867MHz DDR3 SDRAM

AMD Radeon R9 M395 with 2GB

OS X 10.14.5

The first iMac was flickering a lot more. I ended up taking it to an Apple store where they kept it and ran several long tests and reported that nothing was wrong with the hardware. They reformatted the drive, and I reinstalled Office and the flickering returned. I kept narrowing down possibilities, and on both iMacs, we later noted that the flickering occurred when the Outlook client was running. 

Simply restarting, and not using Outlook, the flickering DOES NOT happen. This morning, out of habit, the users started Outlook and both iMacs began flickering.

I have had both users to go webmail, however, I just read that putting the application in low-resolution solves the flicker for others (which we’re currently trying and I’ll report back on, and yes, it looks lousy).

I hope that Microsoft will resolve this issue with the update.

Thanks for the tip.  I did what you recommended as a workaround and so far no flickering...but boy..it looks TERRIBLE/AWFUL (blurry text, pixelated, etc.). Can’t do it.

What I have done is stepped UP the resolution (default is 2560 x 1440) to 2880 X 1620.  So far so good. Weird right.  Something about the default display doesn’t sit right with Outlook.  Will let you know if this resolves it.