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

Hi AussieFlem,

From your description, the issue only happens when Outlook for Mac client is opened. While from my test in the lab, I cannot reproduce this issue with the same Outlook client version and Mac OS version. So as you mentioned, the issue could be a hardware issue and running Outlook client could be a trigger.

Of course, you can try to download Outlook Reset Preference tool to reset the customization in Outlook > Preference and check if it helps. Meanwhile, it's a good idea to update to Office Insider version to verify if the issue still happens in version 16.20. If so, it would be better to change your iMac.

Regards,

Marvin

Hi AussieFlem,

If you have any progress on this issue, just let me know at your earliest convenience.

Regards,

Marvin

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

If I don't run the Outlook app the Mac runs like clockwork.

With Outlook active, at some point the flickering begins and then gets progressively worse until the screen is completed fuzzed or it pops back to a half black screen (which continues to flicker intermittently - more often than not)

Whilst it sounds like a hardware issue (and I've ordered a new Mac thinking it was!) it appears to be tied to Outlook.

iMac (Retina 5K, 27-inch, Late 2015)

3.3 GHz Intel Core i5

8 GB 1867 MHz DDR3

AMD Radeon R9 M395 2048 MB

Mac OS 10.14.1 (18B75)

Outlook 16.19

Rebooting seems to clear it until we run Outlook again, then the cycle continues.

Hi AussieFlem,

Can you please confirm if you have resolved this issue as we are experiencing exactly the same issue. We have taken the iMac to Apple and had the logic board replaced but still have this problem. Like you, we have narrowed this down to Outlook causing the problem and none of the updates have fixed it. This issue definitely started after an Office update a while back. I have also completely wiped the drive and reinstalled everything from scratch (not a restore) so the issue would appear to be with Outlook and not hardware or preferences.

Please do update as I don't know what else to try!

Thanks, Luke.

Hi Luke.

Not resolved - I've replaced the suspect machine.

New iMac is not having the same issue.

Original problem unit I've narrowed down the problem - seems to be OK with Outlook and office, it's Skype for Business that seems to be the trigger (possibly in conjunction with Outlook).

If I run Outlook I'm generally OK.

If I run Skype as well, I get the same issue.

Hi AussieFlem,

This is very helpful and I think you're right, although we don't have Skype for Business, we just run normal Skype. However, the iMac was fine until I was asked to reinstall Skype, then within 30 minutes the issue returned so the problem is clearly there.

Would be nice if Microsoft accepted responsibility for this rather than trying to blame hardware or macOS as this issue clearly appeared after an update around October time.

Lets see if they fix it or advise us to get a new iMac as previously suggest!

Thanks, Luke.