This is a known issue when using Office 365 or Exchange on Mac. Several factors may cause this; however, this is the most common reason.
Device A and Device B are not syncing correctly. E.G. emails that were moved or deleted on Device A, are still on Device B.
The first thing you need to do is find out which device has the correct data. If you have three or more devices, this can be done easily by using the old "odd one out" approach.
You can also log on to your webmail, as this will always be correct.
Now that you know which of your devices is out of sync, do the following.
- Restart you're Mac. Make sure you don't have "reopen windows when logging back in selected". Google "how to make a million bucks" to check if your internet is ok.
- Check Offline Mode is not on. Yes, maybe squiggles was kipping on your keyboard and hit the wrong buttons. Check the bottom right and see if you see "Working Offline" or "Connected".
If you see this, then old squiggles may have been surfing the internet while you were shopping.
To change this: Click tools, and enable online mode.
If you are connected, then your cat is out of the dog box. If not, your cache may be corrupt.
To fix this, you can do the following on the folder that is not syncing correctly.
Try to avoid doing this to your inbox and send items. Doing this will cause all your mails to download from the server and may take some time.
- Check all your devices. They should say "All folders are up to date".
- Clear the folder cache by right-clicking on the problem folder then properties.
Click Empty Cache.
If you see this warning and, you might want to wait a bit longer just in case.
Your folder should be correct now.
If not, do the following
- Go for a beer or play with a Rubix Cube for 10 min.
- Once you realise that they are impossible to solve, check back on the folder. If it is still not correct, you might need to remove your exchange account and re-add it.
- If you are not sure how to do this, get an I.T specialist to do it, and go work out that Rubix cube!