You click a PDF in Gmail and instead of Gmail's preview, Chrome opens a new tab, or Adobe Acrobat opens a chrome-extension:// tab.
1. Check how you click
Ctrl+click (Cmd+click on a Mac) and middle-click open links in a new tab on purpose. Click the attachment card normally, not the download or open icons that appear when you hover.
2. Stop Acrobat from taking over Gmail
This is the most common cause. With Adobe Acrobat for Chrome installed, Gmail's native PDF click is taken over by Acrobat.
- Click the puzzle icon in Chrome's toolbar.
- Click Adobe Acrobat, then the three-dot menu, then Options.
- On Adobe Acrobat preferences > General, under Open PDFs in Acrobat from your browser, uncheck Gmail.
- Reload Gmail.
Or turn the extension off in chrome://extensions. Full steps: Adobe Acrobat extension and Gmail PDFs.
3. Test in Incognito
In an Incognito window (Ctrl+Shift+N) extensions are off by default. If PDFs preview there, an extension is the cause; find it by turning extensions back on one at a time.
Keep PDFs inside Gmail
Attachment Preview adds a Preview button under every PDF and image in Gmail. It opens the file in a viewer on top of your inbox, so you stay in the thread, and nothing downloads. Press Esc to close. Checked in real Gmail: Preview still opens while the Acrobat extension is installed and enabled.
Questions
Why does it work in Edge but not Chrome?
Extensions are installed per browser. If Chrome has a PDF extension that Edge does not, Chrome will behave differently.
Do I lose anything by turning off the Adobe extension?
Only its features inside Chrome. The Acrobat Reader desktop app still works for files you download. You can also leave Acrobat on and only uncheck Gmail in its Options (step 2).
Related: Gmail PDF preview not working