Using classic Outlook for Windows in business environments
Hi @Conrad Nason ,
Welcome to our forum!
Does this issue occur recently? If so, have done any specific operations before?
Based on my test on Outlook 365(version 2111(Build 14701.20262 Click-to-Run)), everything in calendar is working properly, which doesn't reproduce your issue. So, what's the version of the users' Outlook? (File > Office Account > About Outlook). Please make sure they have upgraded your Outlook to the latest version.
Considering the impact of some add ins, It is suggested that you try to start outlook in safe mode(win+R>type: outlook /safe) to check whether it works normally. If it doesn't work, considering the impact of some third-party programs on your computer, please try to perform a clean boot for windows and check if the issue still occur.
As I know, sometimes profile damage will also appear abnormal, it is suggested that you could try to create a new profile(control pane>mail>show profile>new) and add the account to check if there are some differences.
In addition, considering the impact of mouse drivers, I have done a lot of research. In some threads, I found that after the user updated the mouse drivers, the similar issue occurred. His solution is to remove a handful of the preloaded HP software, and then it appears to be ok. It's suggested that you could check the same settings.
Hope the above help!
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