Pop-up message: “The Microsoft Jet database engine cannot open the file ‘C:\Program Files(x86)\1and1Mail\tnedm.ado’. It is already opened exclusively by another user, or you need permission to view its data.”

Please follow the steps below to resolve the issue:

  1. Right click the 1and1Mail icon on your Desktop
  2. Select “Properties”
  3. Go to “Compatibility” tab.
  4. Select the last option “Run as an administrator”.

And then run 1and1Mail.