Why won't my .gdoc file open in Word?

Because it is not a document. It holds a few lines of text pointing to the real document in Google Drive, so there is nothing for Word to open. Open the document on Google instead, and download it as a .docx from there if you need a Word file.

I copied my Drive folder to a backup and only have .gdoc files. Is my work lost?

Not if the Google account still exists: the documents are in that account's Google Drive. To back up the documents themselves, download them from Google Drive, or use Google Takeout (takeout.google.com), which saves Docs, Sheets and Slides as Office or PDF files.

The link says I need permission. Why?

The document belongs to the Google account named on this page. Sign in to that account, or ask its owner to share the document with you.

Is the shortcut file uploaded?

No. It is read by this browser tab on your own device. The link is made from the document's ID on this page and goes straight to Google; nothing passes through this site.

Stays on your computer How this works

Open a GDOC, GSHEET or GSLIDES file: what Google Drive shortcuts are

A .gdoc, .gsheet or .gslides file is a shortcut to a document in Google Drive, not the document. Drop one here to see what it points to and which Google account it belongs to, and open it on Google. The file is read in your browser and is not uploaded.

Drop a .gdoc file here, or click to choose oneIt is opened by your browser, on this computer. Nothing is uploaded.

About Google Drive shortcut files

Google Drive for desktop syncs your Drive to a folder on your computer, but Google Docs, Sheets and Slides do not exist as files: they live on Google's servers. So in their place it puts a tiny shortcut file - .gdoc for a document, .gsheet for a spreadsheet, .gslides for a presentation, and a few others - that holds only the document's ID and the account it is in. Double-clicked on a computer with Drive signed in, it opens the document in the browser. Copied to a USB stick, emailed, or opened anywhere else, it does nothing, and Word or Excel cannot read it because there is nothing in it to read.

This page reads the shortcut and tells you what it points to and whose account it belongs to, with a link to open it on Google. It cannot show the document itself: that is only on Google Drive. It is free to use, with no account and no upload limit, and it runs entirely in your browser: nothing is uploaded, and while the page stays open, a feature you have already used keeps working offline.

What you can do

See what a .gdoc, .gsheet, .gslides, .gdraw or .gform file points to
See which Google account the document is in
Open the document in Google Docs, Sheets or Slides with one click
Learn how to get a real copy you can keep: Word, Excel, PowerPoint or PDF

How to open a GDOC file

Drop the .gdoc, .gsheet or .gslides file on the box above, or click the box and choose it.
Choose Open it in Google Docs (or Sheets or Slides), signed in to the account the page names.
To keep a copy, choose File > Download in Google Docs and pick Word, PDF or another format.

Questions

Why won't my .gdoc file open in Word?: Because it is not a document. It holds a few lines of text pointing to the real document in Google Drive, so there is nothing for Word to open. Open the document on Google instead, and download it as a .docx from there if you need a Word file.
I copied my Drive folder to a backup and only have .gdoc files. Is my work lost?: Not if the Google account still exists: the documents are in that account's Google Drive. To back up the documents themselves, download them from Google Drive, or use Google Takeout (takeout.google.com), which saves Docs, Sheets and Slides as Office or PDF files.
The link says I need permission. Why?: The document belongs to the Google account named on this page. Sign in to that account, or ask its owner to share the document with you.
Is the shortcut file uploaded?: No. It is read by this browser tab on your own device. The link is made from the document's ID on this page and goes straight to Google; nothing passes through this site.