I have the same issue, and had it before. I've always worked from my dropbox folder, so I can leave my house and when a client really needs something, I can access everything from elsewhere.
I've read the ' solution' , but it's a workaround. It's not solved. I used this workaround last year too. And this lead me to forgetting to start dropbox again after I quit it, and I would tell my clients the files are there, leave the house, and no they were not there because Dropbox wasn't synching .
If I have to manually start and stop the synching process, I might as well use Wetransfer to send my work to my clients. I decided for Dropbox so I DON'T have to worry about all of this.
For me the issue started again when I installed a new SSD in my system (no, not an external drive), dedicated for my work and Dropbox. Windows drive is for windows only. Anything else is not on C. For any professional app/service, this should by default not be any issue whatsoever.
DB as a company (in help files and here) tells me I can relink to a new folder, but in reality this is not the case. I have to do it manually, log out of the app, which renders the state of the app as being installed fresh. The only thing it can do is create a new db folder (the app doesn't give other options), and I have to manually move the content to the new db folder. Unfortunately, then this problem with Photoshop occurs.
This relinking option not there is something DB hasn't dealt with. There's a topic about this from 10 years ago. The option still isn't there. People somethimes have to move stuff to other drives in their system, but it creates problems. The first time I had this problem, it was also because the DB folder was relocated.
First time I asked DB for help, I was told it's a Windows problem. So I use the DB app, move the folder with a workaround as instructed by Dropbox, and it's a Windows problem. Hmmm..
I'm thinking.. why do I see so many problems 'solved' with a workaround. I've learned that workarounds are temporary solutions, and in the meantime the probem is being solved. But it's not.. being solved.
Please fix this issue, for real. I know what when I reinstall my entire system, the issue with Photoshop is resolved and I can save and synch every second if I wanted to. But I shouldn't have to do this, right?