Are you running Microsoft Outlook and getting the following popup when trying to dismiss/delete a reminder? “Cannot Turn Off Reminder. You may be reminded again. Could not complete the operation. One or more parameter values are not valid.”
Microsoft Outlook Error
Below are a couple things you can try to get rid of those corrupted/stuck reminders.
There is a great tool called MFCMAPI. MFCMAPI uses Microsoft’s published APIs to provide access to MAPI stores through a graphical user interface. Its purpose is to facilitate investigation of Exchange and Outlook issues and to provide developers with a canonical sample for MAPI development.
When you first launch the tool, you will want to go to “Session” and click on “Logon.”
Choose the Outlook profile you are having problems with. By default you will most likely only have one, “Outlook.”
Right click on your mailbox and select “Open Store.”
Select “Finder” and then right click on “Reminders” and select “Open contents table.”
Be careful on this step. You don’t want to select all of them and delete, otherwise you will lose all of your reminders. Search for and find the specific reminders that you cannot turn off or dismiss, right click on them and select “Delete message.”
You can then exit the tool, launch Microsoft Outlook and hopefully your reminder will now be gone!
The second solution would be to simply wipe the local Outlook profile by going into “Mail” in the control panel, deleting the profile and then rebuilding it. You could also temporarily turn off cached Exchange mode. This would most likely fix your problem right away, however I don’t recommend this as a long term solution. Obviously if the errors are happening when in cached mode, there is a problem somewhere that you need to resolve. But if you want to turn off exchange cache mode simply go into the email properties of your mailbox in Outlook and uncheck “Use Cached Exchange Mode.”
You can also start Microsoft Outlook with the /clean reminders flag and it will rebuild your reminders. To do this, simply go to Run and type Outlook /clean reminders.
Hopefully out of those three solutions one of those will work for you!