Alerts/Reminders dont pop up

[Roger Roger]

Hi experts

for one of my user Alerts/Reminders dont appear. please guide me to troubleshoot

[#2]

Do you mean reminders in the Outlook client? if yes, you can try the steps described here https://support.microsoft.com/en-us/help/2787708/reminders-in-outlook-do-not-appear

[#3]

i checked with end user, he says he is getting alerts but in last one month he did not receive 3 alerts and these are important for them. they get alerts/reminders daily. so how do i troubleshoot this issue.

i was reading  outlook.exe /cleanreminders but i am afraid using it.

will outlook.exe /cleanreminders will repair corrupted reminders ?
will it cause any issues to current running reminders?
Will it dismiss any current reminders(lets say if it dismisses is there any way to restore them)