Adobe Acrobat allows users to customize the window that appears when a user opens PDF documents. By default, the menu bar, toolbar and other interface elements will display. If no menu bar appears when you open the PDF file, how to show or unhide the menu bar in Acrobat?
Press F9 key to show Acrobat menu bar
If you hide the Acrobat menu bar from View menu > Show/Hide > Menu Bar, you can’t unhide it from the menu. To make the menu bar reappear, simply press F9 key(Windows) or Command+Shift+M(Mac OS).
In browsers, such as IE for Windows 10 and Firefox, you can easily unhide the menu by right clicking on the top of the window. The Menu bar can be found in the pop-up context menu. I think Adobe should do this too instead of hiding the most useful functions behind hotkeys.
Relaunch Adobe Acrobat to display its menu bar
Sometimes however you may find the F9 hotkey can’t bring back the Menu bar in Adobe Acrobat or Reader because of hotkey conflict. Other tools or even your computer is using this shortcut.
In such case, you can try closing & reopening which should solve the problem. Acrobat shouldn’t hold the settings when you relaunch it. Thus you can make the menu bar of Acrobat appear again.
Update Apr 2019: removed amzn.