Saving a document in Word 2016 involves working with both Word and the Windows operating system. This process doubles the chances of something going wrong, so it's high time for an error message. One such error message is
The file whatever already exists
You have three choices:
Replace Existing File: Nope.
Save Changes with a Different Name: Yep.
Merge Changes into Existing File: Nope.
Choose the middle option and click OK. Type a different filename in the Save As dialog box.
Another common problem occurs when a message that's displayed reads something like this:
The file name is not valid
That's Word's less-than-cheerful way of telling you that the filename contains a boo-boo character. To be safe, use letters, numbers, and spaces when naming a file.
Be creative in your document, but also be creative when saving the document and christening it with a name. These names must abide by the Windows rules and regulations for all filenames:
A filename can be longer than 200 ridiculous-something characters; even so, keep your filenames short but descriptive.
A filename can include letters, numbers, and spaces, and can start with a letter or a number.
A filename can contain periods, commas, hyphens, and even underlines.
A filename cannot contain any of these characters: / : * ? " < > |.
Word automatically appends a filename extension to all documents you save — like a last name. You may or may not see the filename extension, depending on how you've configured Windows. Either way, don't type the extension. Only concern yourself with giving the document a proper and descriptive filename.