Reminders waking iMac from Sleep

OK, so here is a quick update after a week dealing with Apple Support trying to get to the bottom of this...

1. A Senior Advisor at Apple escalated my issue to their engineers who came back yesterday saying there is currently a sync issue with reminders, this may explain why various reminders do not complete or sync correctly across all of my devices.
2. One of my suggestions as to why I'm having so many problems with reminders I pointed out could be because I'm a heavy user and the shear number of reminders having to be synced may be causing an issue, especially as I have been using Reminders for years pretty much since it was released, and they've been ported from OS to OS including the most recent. significant upgrade at the end of 2019. When I looked, I had almost 20,000 completed reminders.
3. Apple's engineers said they didn't have the power to wipe my reminders remotely and that I was have to painful delete all 20,000 manually, a task I've been doing over the past week. I now have 0 reminders scheduled or completed in my iCloud.
4. Creating a new reminder with an alert time *no longer* wakes my iMac up from sleep (hurrah), however I am still experiencing significant syncing issues. Any new reminder I set on any of my devices (iMac, MacBook Pro, iPhone, iPad or iCloud) fail to sync across any of my reminder apps, something is seriously wrong.
5. I have also noticed that despite my notifications being turned on on my iMac, none of them are working across any of my apps, which leads me to believe there is something fundamentally wrong with the notifications on my iMac and maybe it's not just a reminders issue.

To sum up, I'm none the wiser after 2 weeks of testing - without Apple or myself able to get my Reminders and notifications working I find myself seriously considering moving everything to the 'Microsoft To Do' app (formerly Wunderlist) which has raving reviews and seems to be working like a dream over the past week...

Unfortunately not, after a few days I heard back from Apple Support saying their engineers are unable to wipe any of my personal data remotely for data protection reasons - apparently they can't even see my reminders as they are fun encrypted.

I ended up having to manually delete everything (a task I don't wish on my worst enemy, especially one who has 10,000+ exisiting reminders). Unfortunately this has not solved the issue, all of my devices are completely out of sync and no matter how much testing I do, reminders simply refuse to sync correctly and transfer across all of my devices. New reminders continue to wake up my iMac even after deleting everything.

The only way out for me was to complete switch to a new application, so for the past 2 months I've been using Microsoft To Do (previously Wunderlist) which is working like a dream. It took me a good few hours to manually transfer all of my existing reminders over but I don't look back. The app has a few missing features but they regularly update it, but most importantly they sync correctly across all my devices and my iMac remains asleep throughout the day!

Apple appear to be turning a blind eye to this issue, let's just hope the new Mac OS they announce next week at WWDC for release later in the year provides some improvements. But for now, I'm sticking with To Do...

Thanks chris_g1, unfortunately I've already spoken to Apple Support and they are unable to offer anymore help now that I've stepped through all their advice and even restored the Mac.

It appears to be a known issue with Reminders and notifications, I guess we just have to wait for a fix to come out

Just to update everyone, in an attempt to solve this issue I've asked Apple to completely wipe my iCloud reminders. I've been using Reminder for years and must have 10,000+ completed reminders on my account and roughly 200 active ones. I'm wondering whether it is this that is the source of my issues. To get to the bottom of it, I've asked them to wipe my account so I can start fresh and see if that solves the issue as it didn't escape my mind that these issues may have been caused by the upgrade in Reminders in Q3 of 2019. I'll keep you updated...

Hi A13_usr

Thank you for your response, I've seen online that there is a large number of people having the same issue and reporting it. From what I can see it is a bug on Apple's end and as of yet, there is not a fix.

I do have Do Not Disturb setup but unfortunately it has no impact. Your suggestion of auto logging out is a great one, I'll set it up now and hope that this workaround fixes the issue.

Thank you again.

Hi A13_usr, unfortunately logging out did not temporarily solve the issue. My Mac simply woke up to the login screen when a reminder was scheduled and the Mac was asleep. Back to square one, I really hope Apple fix this soon. It's infuriating...

Hi MoonJ.

Thank you for the advice however I've already done the reboot into Safe Mode with Apple Support as well as setting up a new user and neither of those fixed it. From listening to the advice on other support pages restoring the Mac to factory settings and installing MacOS also has little success so I guest I'm just going to have to wait this out until Apple come up with a bug fix...

Yes, it has no effect. The other users reporting the same problem say the same...