My iMac slowed down considerably (1/2 hour before I could do anything!!!!)
I installed Mac OS X Mojave on an SSD; copied 51 GB of "Documents" to my "last ditch backup" disk, deleted the old files, emptied Trash and copied back the "Documents". (I checked the sizze and a random sample of files/documents -- all good.)
I restarted the computer using the SSD.
The "start up" shortcuts have disappeared, including the Dropbox ico in the menu bar.
I started "Dropbox" from Applications; the message said I was using an outdated version.
I could not find Dropbox in the AppStore! I downloaded Dropbox from the website and installed it / TRIED to install it.
I signed in and got the message that I was trying to use more than three devices -- I WAS NOT! (I use one iPhone, one iPad and one iMac.)
You mentioned that you're currently paying for Dropbox, which plan are you using? Only the Basic free account has a limit for 3 devices. You can check your current plan from your Plan page here.
Also, if you're only using 3 devices it could be that one of the old device wasn't fully disconnected from your account previously. You can check for and unlink any old devices from your security page here.
Thanks, Daphne, my query and the point are now moot!
I had installed the SSD to try to speed up my iMac, which was s-l-o-w because of (I'm fairly certain) the disk fragmentation and the fact that the System, Applications and all the data were on the one HD. While the SSD-based Mojave did work, ALL my preferences, "recent" files etc. had gone away, and documents which I updated appear to have been filed in a location pointed to by the "new" user home directory! The result was that it took me more time to do things than on the "slow" system!
Net result? I switched back to the HD-based system and Dropbox again recognised my iMac, as well as my iPad and iPhone, so I did not check further. I will do so when I have caught up on my backlog!
Thank you for your interest and care in replying to my post.