I can't figure out why the developers of dropbox have to over-complicate simple things like "selecting all files". I finally found directions how to do it and it's just plain stupid and doesn't always work.
"Selecting multiple "Selecting multiple files Click on the file row to the right of the file's name to select it. (Clicking on the file name or icon will open the file as a preview.) Hold the Shift key and then click on or use the up/down arrows on your keyboard to select another file in the file browser."
Why can't you just make it "ctrl-a" like everybody else in the world? Why make technology harder to use for NO REASON.
CTRL-A already does select all files and folders on the screen.
Pressing CTRL-A to select all
If it's not working for you, then it's likely your browser overriding it, since CTRL-A is a default shortcut to select all text on a page in most browsers. It could also be that you're not in focus (the files and folders aren't the active part of your screen). Try selecting one item, then press CTRL-A.
I've called dropbox, tried several browsers (chrome, firefox, safari) but no boxes appear to check so I have to go to my friends house and borrow his computer... no other way to do this. DROPBOX SUCKS I keep telling my boss to move to a better system.
If it works on your friend's computer, then the problem is likely something on your computer. Possibly an add-on or extension that you're running in your browsers. The ability to select all files works just fine, as seen in the screenshots above.
Also note that Dropbox only provides phone support for Dropbox Business accounts. If you have a personal account and try to call Dropbox, you won't be able get through. There is a required PIN that's found in the admin console of Business accounts that include phone support. If you Googled for a Dropbox phone number, the numbers you'll find are mostly all scammers.