Reminders app is not syncing across any of my Apple devices

Uscanuk wrote:

I have an iPhone, iPad, MacBook Pro and iMac and each of them has a different iteration of my Reminders data. Some more complete than others - the new iPhone the least complete and the iCloud Web app containing no Reminders data at all.

Based on your description of each device having different sets of Reminders, seems to mean that you do not have iCloud turned "on" for each device. That is why, there are "no Reminders data" in the "iCloud Web app." Please consider reading the Apple KB article regarding iCloud contacts, calendars, or reminders won't sync at https://support.apple.com/en-us/HT203521.

Basically, you need to go to the System Preferences (on Macs) and Settings (on iDevices), then iCloud and slide the tab next to Reminders to the right (exposing green) to turn it on. Since you have multiple devices, determine which device has the most complete up-to-date list of Reminders. Turn on iCloud Reminders on that device first. Depending on how many reminders you have, give it a few minutes and then go the iCloud Web app to see if the Reminders from the Mac are there. If yes, then turn iCloud Reminders "on" on all your other devices. If you still have issues, go back through the article step-by-step.

Hope this helps.

Uscanuk wrote:

Since I purchased and transferred my data to a new iPhone 13 my Reminders app has not been syncing data across any of my devices as well as the online iCloud web app. I have an iPhone, iPad, MacBook Pro and iMac and each of them has a different iteration of my Reminders data. Some more complete than others - the new iPhone the least complete and the iCloud Web app containing no Reminders data at all.

I've seen others on these boards having the exact problem with Reminders recently and yet have not seen a solution from Apple support that helps.

Please help. The Reminders app is an important part of my workflow.

To sort sync issue— sign out of iCloud and back in

>System Preferences>iCloud>Sign out

Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac

https://support.apple.com/en-us/HT208242