Outlook – Cannot dismiss or snooze reminders

Several possible solutions, so let's try from the easiest ones and work our way up :-)

[1] Click on File -> Options -> Advanced
In 'Reminders' section check to see if 'Show reminders' is checked.

[2] Start Outlook with '/cleanreminders' command
(Start -> Run -> outlook /cleanreminders)

[3] Start Outlook with '/cleanfreebusy' command
(Start -> Run -> outlook /cleanfreebusy)

If none of this helps you out, let me know.
There are other things we can try, but you may not like them.

Edit:
[4] A corrupted reminder
Now you'll see why this may be the solution you will like if you have many of them :-(
Open Calendar, click on View -> Current View -> Recurring appointments.
Opened each one of them until you get the error "Recurrence data not found".
Delete this one and you should be all good to go.

Edit 2:
[5] Corrupted cache
Are you using Exchange? If so, disable the cached mode and restart Outlook. This will clear the corrupted cache .ost file. Enable cached mode again and restart once more. Outlook will rebuild your cache files from scratch.

[6] Multiple data files
Is it possible that you created more than one data file? Check this by going to Tools -> Options -> Mail setup -> Data Files. It there is another one in addition to your default data file, it's most likely causing this. Oh, and before deleting the not-needed one - Backup! I can not stress this enough.

[7] Outlook with POP3 mailbox
If you are not using Exchange, Outlook will keep all of your reminders in .pst file, as there will be no .ost cache. That may mean the main .pst file is corrupted. Unfortunately, a step-by-step guide will take quite a while for me to write down here, so let's please make sure that you are in fact using POP3 and steps 5 and 6 failed.

[8] If changed from cached exchange mode - check outlook - options - calendar options - delete offline items

Sub SnoozedReminders()

' http://www.jpsoftwaretech.com/check-your-outlook-reminders-in-vba/

Dim MyReminder As Outlook.Reminder
Dim MyReminders As Outlook.Reminders
Dim Report As String
Dim i As Long

Set MyReminders = Outlook.Reminders

i = 0

For Each MyReminder In MyReminders

    If HasReminderFired(MyReminder) = True Then
        i = i + 1
        Report = Report & i & ": " & MyReminder.Caption & vbCr & _
            "     Snoozed to " & MyReminder.NextReminderDate & vbCr & vbCr
    End If

Next MyReminder

CreateReportAsEmail "Snoozed Items", Report

End Sub


Function HasReminderFired(rmndr As Outlook.Reminder) As Boolean
    HasReminderFired = (rmndr.OriginalReminderDate <> rmndr.NextReminderDate)
End Function


' VBA SubRoutine which displays a report inside an email
' Programming by Greg Thatcher, http://www.GregThatcher.com

Public Sub CreateReportAsEmail(Title As String, Report As String)

    On Error GoTo On_Error

    Dim Session As Outlook.Namespace
    Dim mail As MailItem
    Dim MyAddress As AddressEntry
    Dim Inbox As Outlook.folder 

    Set Session = Application.Session
    Set Inbox = Session.GetDefaultFolder(olFolderInbox)
    Set mail = Inbox.items.Add("IPM.Mail")

    mail.Subject = Title
    mail.Body = Report

    mail.Save
    mail.Display

Exiting:
    Set Session = Nothing
    Set Inbox = Nothing
    Set mail = Nothing
    Exit Sub

On_Error:
    MsgBox "error=" & Err.Number & " " & Err.Description
    Resume Exiting

End Sub

If you are unfamiliar with VBA see Slipstick's explanation page. You will find information about:

• macro security settings;
• where to put the code (You can use a regular module with Insert | Module); and
• how to create a button.