Error: The outline is too long to read in its entirely
This error message can appear for some users when attempting to open PowerPoint and there was a previous COM error or you are trying to open a very large powerpoint presentation or powerpoint template. Especially if you are a developer and tried to call the Interop libraries you may experiment this error when you open powerpoint for the next time.
A possible solution could be opening running programs and services and locate the powerpoint program. Then stop it and try to run it again.
In Windows you can do this by pressing CTRL-ALT-DEL and then Start Task Manager.
Then locate POWERPNT.EXE that is the running process and stop it.
Now, start powerpoint again as usual and the error should have gone.