Hi, today I've seen this error: "Unable to load 'xyz.dll'. You may be out of memory, out of system resources, or missing a .dll file". I don't understand a thing.
This indicates that Outlook is trying to load something that isn't there. To overcome this, I recommend a fresh installation of Outlook, or if you recognize the DLL file that's missing, reinstall the add-on or plug-in. This works in most of the cases without messing all the database created by Outlook.
Use the following guide to disable/enable plugins in Outlook: https://support.office.com/en-us/article/Enable-or-disable-add-ins-in-Office-programs-3e533d0f-a6cf-44b7-b6b4-3d9185b5e025