external sheet references
How to remove the references to the external file, is It by double clicking like you mentioned in "Be even quicker: f5+ enter" ?
Please explain again, with every step.
There are two main ways to do this. One is to copy the name of the external file and to use Find and Replace and change formula references to the external file. This is how I usually do this.
The second (more traditional) option is to the Data tab and click on Edit Links. Here you can replace the links to the External file.